Substituted guanidines having high binding to the sigma receptor and the use thereof

ABSTRACT

N,N-disubstituted-guanidines, e.g., of the formula ##STR1## wherein R and R&#39; are substituted or unsubstituted hydrocarbon groups. Methods are provided for the treatment of psychosis and hypertension by administering an effective amount of an N,N&#39;-disubstituted guanidine which, preferably, has a high affinity for the sigma receptor.

STATEMENT AS TO RIGHTS TO INVENTIONS MADE UNDER FEDERALLY SPONSOREDRESEARCH AND DEVELOPMENT

This invention was made with government support under Grant No. MH 40303awarded by the National Institutes of Health. The government has certainrights in the invention.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application is a continuation of application Ser. No.07/528,216 filed on May 25, 1990, now abandoned, which is acontinuation-in-part of U.S. application Ser. No. 07/254,068, filed Oct.6, 1988, now abandoned; which is a continuation-in-part of PCTApplication No. PCT/US87/01545, filed Jun. 26, 1987; which is acontinuation-in-part of U.S. application Ser. No. 06/884,150 filed Jul.10, 1986, now U.S. Pat. No. 4,709,094, the disclosures of which arefully incorporated by reference herein. The present application is alsoa continuation-in-part of U.S. application Ser. No. 07/346,494, filedMay 2, 1989, now abandoned, the disclosure of which is fullyincorporated by reference herein.

FIELD OF THE INVENTION

The invention is in the field of medicinal chemistry. In particular, theinvention relates to substituted guanidines which bind to the sigmareceptor and pharmaceutical compositions thereof which are useful forthe treatment of psychotic mental illness and hypertension in animals.

BACKGROUND OF THE INVENTION

Recently, the inventors have described a series of di-aryl-guanidineswhich are potent ligands for brain sigma receptors (Weber, et al., PNAS(USA) 83:8784-8788 (1986); Campbell et al., J. Neurosci, 3380-3391(1989); U.S. Pat. No. 4,709,094). Brain sigma receptors bind manypsychotropic drugs (Sonders et al.. Trends Neurosci. 11:37-40 (1988)).The physiological function of sigma receptors in the nervous system issubject to intense investigations (Sonders et al., Trends Neurosci.11:37-40 (1988)) because certain sigma receptor selective compounds haveknown antipsychotic activity suggesting that sigma receptor activecompounds can be used for the treatment of schizophrenia (Largent etal., Eur. J. Pharmacol. 11:345-347 (1988)).

A wide variety of substituted guanidines are disclosed in the patentliterature. For example:

U.S. Pat. Nos. 1,411,731 and 1,422,506 discloses diphenylguanidine as arubber accelerator;

U.S. Pat. No. 1,597,233 discloses N-o-tolyl-N'-phenyl-guanidine as arubber accelerator;

U.S. Pat. No. 1,672,431 discloses N,N'-di-o-methoxyphenyl-guanidine asbeing useful for therapeutic purposes, especially in the form ofwater-soluble salts;

U.S. Pat. No. 1,730,338 disclosesN-p-dimethyl-amino-phenyl-N'-phenylguanidine as a rubber accelerator;

U.S. Pat. No. 1,795,738 discloses a process for the production ofN,N'-dialkyl-di-substituted guanidines, includingN-di-ethyl-N'-phenyl-guanidine, N-diethyl-N-isoamylguanidine,N-dimethyl-N'-isoamylguanidine and N-dimethyl-N'-ethylguanidine;

U.S. Pat. No. 1,850,682 discloses a process for the preparation ofdisubstituted guanidine rubber accelerators bearing an additionalsubstituent on the imine nitrogen atom;

U.S. Pat. No. 2,145,214 discloses the use of disubstituted guanidines,e.g., diarylguanidines especially dixylylguanidine, as parasiticides;

U.S. Pat. No. 2,254,009 discloses sym-di-2-octyl-guanidine and U.S. Pat.Nos. 2,274,476 and 2,289,542 disclose sym-dicyclohexylguanidine asinsecticides and moth larvae repellents;

U.S. Pat. No. 2,633,474 discloses 1,3-bis(o-ethylphenyl)guanidine and1,3-bis(p-ethylphenyl)guanidine as rubber accelerators;

U.S. Pat. No. 3,117,994 discloses N,N',N"-trisubstituted guanidines andtheir salts as bacteriostatic compounds;

U.S. Pat. No. 3,140,231 discloses N-methyl- andN-ethyl-N'-octylguanidines and their salts as antihypertensive agents;

U.S. Pat. No. 3,248,246 describes (Example 5) a 1,3-disubstitutedguanidine whose substituents are hydrophobic hydrocarbon groups, one ofwhich is naphthylmethyl and the other is n-butyl;

U.S. Pat. No. 3,252,816 discloses various N-substituted andunsubstituted cinnamyl-guanidines and generically the corresponding N'-and N"-alkyl substituted compounds and their salts as antihypertensiveagents;

U.S. Pat. No. 3,270,054 discloses N-2-adamant-1-yl- andN-2-homoadamant-1-yl-oxy-ethyl-thioethyl- and aminoethyl-guanidinederivatives bearing at most two lower alkyl groups on the N'- and/orN"-nitrogen atom as sympathicolytic and anti-viral agents;

U.S. Pat. No. 3,301,755 discloses N-ethylenicallyunsubstituted-alkyl-guanidines and the corresponding N'- and/or N"-loweralkyl compounds as hypoglycemic and antihypertensive agents;

U.S. Pat. No. 3,409,669 disclosesN-cyclohexylamino-(3,3-dialkyl-substituted-propyl)-guanidines and thecorresponding N'-alkyl- and/or N"-alkyl-substituted compounds ashypotensive agents;

U.S. Pat. No. 3,547,951 discloses 1,3-dioxolan-4-yl-alkyl-substitutedguanidines which have anti-hypertensive activity and discloses loweralkyl, including n-butyl, as a possible substituent on the other aminogroup;

U.S. Pat. No. 3,639,477 discloses propoxylguanidine compounds as havinganorectic properties;

U.S. Pat. Nos. 3,681,459; 3,769,427; 3,803,324; 3,908,013; 3,976,787;and 4,014,934 disclose aromatic substituted guanidine derivativeswherein the phenyl ring can contain hydroxy and/or halogen substituentsfor use in vasoconstrictive therapy;

U.S. Pat. No. 3,804,898 discloses N-benzylcyclobutenyl andN-benzylcyclobutenyl-alkyl-guanidines and the corresponding N-alkyland/or N"-alkyl-substituted compounds as hypotensive agents;

U.S. Pat. No. 3,968,243 discloses N-aralkyl substituted guanidines andthe corresponding N'-alkyl-n"alkyl and N',N'-aralkyl compounds as beinguseful in the treatment of cardiac arrhythmias;

U.S. Pat. No. 3,795,533 discloses o-halo-benzylidene-amino-guanidinesand their use as anti-depressants for overcoming psychic depression;

U.S. Pat. No. 4,007,181 discloses various N,N'-disubstituted guanidinessubstituted on the imine nitrogen atom by adamantyl as possessingantiarrhythmic and diuretic activities;

U.S. Pat. No. 4,051,256 discloses N-phenyl- andN-pyridyl-N'-cycloalkylguanidines as antiviral agents;

U.S. Pat. No. 4,052,455 and 4,130,663 disclose styrylamidines, asanalgesics agents or for the prevention of blood platelet aggregation;

U.S. Pat. No. 4,109,014 discloses N-hydroxysubstituted guanidines andthe corresponding N-methyl disubstituted guanidines as vasoconstrictoragents;

U.S. Pat. No. 4,169,154 discloses the use of guanidines in the treatmentof depression;

U.S. Pat. No. 4,393,007 discloses N-substituted and unsubstituted,N-substituted methyl-N'-unsubstituted, monosubstituted anddisubstituted-N"-unsubstituted and substituted guanidines as ganglionicblocking agents; and

U.S. Pat. No. 4,471,137 discloses N,N,N'N"-tetraalkyl guanidines asbeing sterically hindered bases useful in chemical synthesis.

U.S. Pat. No. 4,709,094 discloses 1,3-disubstituted-guanidines, e.g.,1-3-dibutyl-guanidine and 1,3 di-o-tolyl-quinidine, as sigma brainreceptor ligands.

For examples of other substituted guanidines, see, e.g.,

U.S. Pat. Nos. 1,422,506; 1,642,180; 1,756,315; 3,159,676; 3,228,975;3,248,426; 3,283,003; 3,320,229; 3,479,437; 3,547,951; 3,639,477;3,784,643; 3,949,089; 3,975,533; 4,060,640 and 4,161,541.

Geluk, H. W., et al., J. Med. Chem., 12,712 (1969) describe thesynthesis of a variety of adamantyl disubstituted guanidines as possibleantiviral agents, including N,N'-di-(adamantan-1-yl)-guanidinehydrochloride, N-(adamantan-1-yl)-N'-cyclohexyl-guanidine hydrochlorideand N-(adamantan-1-yl)-N'-benzyl-guanidine hydrochloride.

U.S. Pat. No. 4,709,094 (1987), discloses N,N'-disubstituted guanidinederivatives which exhibit high binding activity with respect to thesigma receptor having the Formula (I): ##STR2## wherein R and R' are analkyl group of at least 4 carbon atoms, a cycloalkyl group of 3-12carbon atoms, or carbocyclic or aryl, of at least 6 carbon atoms.

Two of the novel N,N'-disubstituted guanidines disclosed therein arealso claimed therein viz., 1,3-di-(4-halo-2-methylphenyl)-guanidine and1,3-di-(4-³ H]-(2-methylphenyl)-guanidine.

Also claimed therein is a method of determining the relationship ofabnormal psychotic-like behavior in a mammal displaying such behavior tosigma receptor system dysfunction, which comprises administering to themammal displaying such behavior a water-solubleN,N'-disubstituted-guanidine which displaces in vitro N,N'-di-(4-[³H]-2-methylphenyl)-guanidine bound to mammalian brain membrane, in anamount effective to alter the sigma brain receptor-modulated mentalactivity of the mammal; a method of treating a human being sufferingfrom a psychotic mental illness associated with hallucinations, whichcomprises administering thereto a water-soluble N,N'-disubstitutedguanidine which is an antagonist to the sigma receptor binding activityof a hallucinogenic benzomorphan, in an amount effective to amelioratethe hallucinations.

In U.S. Pat. No. 4,709,094 is further disclosed a method of determiningthe sigma brain receptor binding activity of an organic compound whichcomprises the steps of a) contacting in an aqueous medium a known amountof isolated mammalian brain membrane which has sigma receptor-likebinding activity, with a mixture of (i) a tritium labeledN,N'-disubstituted guanidine which selectively binds sigma brainreceptors, in a known amount capable of being bound to the sigmareceptors of that brain membrane; and (ii) varying known amounts of awater soluble organic compound to be assayed for sigma receptor bindingactivity; b) separating the brain membrane from the tritium labeledcompound which is not bound to the brain membrane in step a); and c)determining, from the molar relationship of the proportion of boundtritium-labeled compound which is separated in step b) to the molaramount of the organic compound employed in step a), the sigma receptorbinding activity of that organic compound.

Certain benzomorphan opiates, such as N-allyl-normetazocine (SKF 10,047)and cyclazocine, in addition to analgesia, cause hallucinations,depersonalization, drunkenness and other psychotomimetic effects in man.In monkeys, dogs and rodents the psychotomimetic opiates causebehavioral and autonomic effects that are unlike those observed withadministration of classical opiates such as morphine or the opioidpeptides. Specific sigma "opioid" receptors in the brain are believed tomediate such atypical effects. Martin et al., J. Pharmacol. Exo. Ther.197:517-532 (1976). It is believed that the sigma receptors also mediatesome of the psychotomimetic effects of phencyclidine [PCP, angel dust],or alternatively, that psychotomimetic opiates act at specific PCPreceptors. Zukin, R. S., et al., Mol. Pharmacol. 20:246-254 (1981);Shannon, H. E., J. Pharmacol. Exo Ther. 225:144-152 (1983); White, J.M., et al., Psycho-pharmacology 80:1-9 (1983); and Zukin et al., J.Neurochem. 46:1032-1041 (1986). PCP is a drug of abuse that causes abehavioral syndrome in man similar to that which is observed inschizophrenic psychosis. Aniline, O., et al., CRC Critical Rev. Toxicol.10:145-177 (1982). Because of the potent psychotomimetic effects ofsigma opiates and PCP, it is believed that sigma (and/or PCP) receptorsplay a role in mental illness, particularly schizophrenia.

A systematic investigation of the role of sigma receptors in normal andabnormal brain function has been hindered by a lack of specific sigmareceptor binding assays and bioassays. Development of such specificassays requires well-characterized, highly selective and potent sigmareceptor ligands. Recent studies have shown that brain membranereceptors can be labeled in vitro with (+)[³ H]SKF 10,047, Su, T. P., J.Pharmacol. Exo. Ther. 223:284-290 (1982); (+)[³ H]SKF 10,047, Tam, S.W., et al., Proc. Natl. Acad. Sci. U.S.A. 81:5618-5621 (1984); Martin etal., J. Pharmacol. Exo. Ther. 231:539-544 (1984); and Mickelson, M. M.,et al., Res. Commun. Chem. Pathol. Pharmacol. 47:255-263 (1985),although not selectively, Gundlach et al., Eur. J. Pharmacol.113:465-466 (1985); and Largent, B. L., et al., J. Pharmacol. Exo. Ther.238:739-748 (1986), and with (+)[³H]3-(3-hydroxyphenyl)-N-(1-propyl)-piperidine ((+)[³ H]3 -PPP), Largentet al., Proc. Natl. Acad. Sci. U.S.A. 81:4983-4987 (1984), which isapparently more selective for sigma receptors than the others.

After the initial in vitro studies by Martin et al., (1976) supra. Keatsand Telford (Keats, A. S., et al., "Analgesics: Clinical Aspects." InMolecular Modification in Drug Design, R. F. Gould (ed.), Advances inChemistry Series #45 Amer. Chem. Soc., Wash. D.C. (1964)), and Haertzen(Haertzen, C. A. Cyclazocine and Nalorphine on the Addiction ResearchCenter Inventory (ARCI), Psychopharmacologia (Berl.) 18:366-377 (1970)),numerous investigators set out to biochemically characterize thedifferent opiate receptors (mu receptors, kappa receptors and sigmareceptors) in vitro.

The first evidence for the existence of a separate sigma receptor intest tube experiments was provided by Su (1982) supra in a paperdescribing an etorphine-inaccessible binding site in guinea pig brainmembranes which was apparently selectively labeled by tritium-labeledSKF-10,047. To overcome the fact that SKF10,047 could label multipleopioid receptors in the brain, Su performed his receptor binding assayusing tritium labeled SKF-10,047 in the presence of excess unlabeledetorphine. Etorphine is a very strong opiate agonist drug which is knownto bind to delta receptors, mu receptors and kappa receptors with almostequal potency. Su used etorphine to saturate all mu, kappa and deltareceptors in a brain membrane preparation and then added tritium labeledSKF-10,047. This enabled him to detect a sigma binding site that wasapparently different from mu, kappa and delta receptors.

A major breakthrough in identifying the sigma receptor as a separateentity occurred when Tam et al. (1984), supra, demonstrated that theprevious problems in selectively labeling the sigma receptor were causedby the fact that in all previous experiments a racemic SKF-10,047preparation was used. Tam showed that using a tritium labeled(+)-SKF-10,047 isomer one could selectively label a sigma receptor thatwas different from the mu, delta and kappa opioid receptors. On theother hand, Tam showed that (-)-SKF-10,047 apparently labeled the mu andkappa receptors but not the sigma receptors. Tam, S. W., Eur. J. Pharm.109:33-41 (1985). This finding has now been confirmed. (Martin et al.,1984, supra). Moreover, there is evidence from behavioral experiments,Khazan et al., Neuropharm. 23:983-987 (1984); Brady et al., Science215:178-180 (1981), that it is the (+)-SKF-10,047 isomer that is solelyresponsible for the psychotomimetic effects of SKF-10,047.

One of the most important findings of the biochemical characterizationof the sigma receptor has been that this receptor binds all syntheticopiate drugs that are known to have hallucinogenic and psychotomimeticeffects. Opiates that do not have psychotomimetic effects in vivo do notbind to this receptor. Most importantly, it has been shown that besideshallucinogenic opiate drugs, the sigma receptor also binds manyantipsychotic drugs that are used clinically to treat hallucinations inschizophrenic patients. (Tam and Cook, 1984). The initial observationswith regard to antipsychotic drug binding to the sigma receptor (Su,1982) were subsequently extensively confirmed and extended by Tam et al.(1984), supra, also showed that when one used radioactively labeledhaloperidol, one of the most potent antipsychotic drugs that is usedclinically, about half of the binding sites in brain membranepreparations are actually sigma receptors whereas the other half of thebinding sites are apparently dopamine receptors. It has long been knownthat most antipsychotic drugs are also dopamine receptor antagonists.Previously the beneficial actions of antipsychotic drugs in psychoticpatients have been attributed to the dopamine receptor-blocking effectof these drugs. It is clear from the work by Tam, however, that numerousclinically used antipsychotic drugs also bind to the sigma site. Allanti-psychotic drugs that bind to the sigma receptor may in part causethe beneficial effect of alleviating hallucinations through the sigmareceptor. Taken together all these observations suggest the sigmareceptor as a prime candidate to be involved in the pathogenesis ofmental illness, particularly schizophrenia in which hallucinations are amajor clinical symptom.

Deutsch, S. I., et al. (Clinical Neuropharmacology, Vol. 11, No. 2, pp.105-119 (1988)) provided a review of the literature which implicates thesigma receptor site in psychosis and anti-drug efficacy. According toDeutsch et al., certain benzomorphans which possess analgesic potency inhumans are also associated with a high incidence of psychotomimeticeffects. It has now been concluded that the analgesic action isassociated with the levorotatory isomers of racemic mixtures of thebenzomorphans, while the psychotomimetic effects are attributable to thedextrorotatory isomers in the racemic mixtures. See Haertzen, C. A.,Psychopharmacologia 18:366-77 (1970), and Manallack, D. T., et al.,Pharmacol. Sci. 7:448-51 (1986). Coupled with the fact that many of thein vivo effects of these dextrorotatory enantiomers and the binding ofdextrorotatory tritiated SKF-10,047 are not antagonized by naloxone ornaltrexone, these data strongly support the concept that thepsychotomimetic effects of the dextrorotatory enantiomers are associatedwith the sigma receptor binding site.

Further, Su, T. P., et al. (Life Sci. 38:2199-210 (1986)), andContreras, P. C., et al. (Synapse 1:57-61 (1987)), have established theexistence of endogenous ligands for the sigma receptor, suggesting thatthe dysregulation of the synthesis, release, or degradation of thesenatural ligands may be a naturally occurring mechanism of psychosis.Accordingly, sigma receptor antagonism provides the potential for aneffective antipsychotic therapeutic treatment. See Ferris, R. M., etal., Life Sci. 38:2329-37 (1986), and Su, T. P., Neurosci. Let. 71:224-8(1986).

As further evidence of the role of the sigma receptor in psychosis, thesubstituted carbazolecis-9-[3-(3,5-dimethyl-1-piperazinyl)-propyl]carbazole dihydrochloride(rimcazole) was identified as a potential antipsychotic agent based onits ability to antagonize apomorphine-induced mesolimbic behaviorsselectively without altering the intensity of stereotypic behaviors.Further, the compound does not accelerate the rate of dopamine synthesisand does not affect dopamine-stimulated production of cAMP inhomogenates of rat striatum and olfactory tubercle, thus establishingthat rimcazole does not exert its action at the level of post-synapticdopamine receptors in the mesolimbic area.

Rimcazole is able to competitively inhibit the specific binding ofdextrorotatory tritiated SKF-10,047, the prototype sigma receptoragonist, suggesting that rimcazole acts at the sigma receptor site.Rimcazole, therefore, shows potential antipsychotic activity in humans,without extrapyramidal effects, pharmacological behavior which isconsistent with its role as a competitive antagonist of thesigmareceptor.

Another compound, BMY 14802, has demonstrated many properties inpreclinical behavioral tests which suggest its efficacy as a potentialantipsychotic agent which is devoid of extrapyramidal side effects. Thecompound (1) did not cause catalepsy in rats; (2) does not inhibit thebinding of [³ H]spiperone to the D2 class of striatal dopamine receptorsin rats; (3) did not increase the maximal density of the [³H]spiperone-labeled D₂ site in striatum even following chronicadministration (20 days) to rats; (4) does not appear to interact withthe D₁ subclass of dopamine receptors; and (5) does not inhibitdopamine-stimulated cAMP production or the binding of [³ H]SCH 23390 invitro. These data suggest that BMY 14802 has a low potential forproduction of tardive dyskinesia and further suggests that theantipsychotic effects would be mediated by a nondopaminergic site.Further, BMY 14802 binds with relatively high affinity to the sigmareceptor, with the binding being stereoselective (the dextrorotatoryenantiomer being 10 times more potent at inhibiting binding than thelevorotatory enantiomer). BMY 14802 does not bind to the adrenergic,muscarinic, cholinergic, or histaminergic sites, suggesting that thecompound would not be associated with unpleasant sedative and autonomicside effects.

Accordingly, compounds which bind selectively to the sigma receptor siteand which antagonize this site may be expected to be usefulantipsychotic drugs which are devoid of extrapyramidal effects.

The antipsychotic and anti-schizophrenia drugs that are currently in usehave very strong side effects that are mainly due to their action ondopamine receptors. The side effects often involve irreversible damageto the extrapyramidal nervous system which controls movement functionsof the brain. Patients under long term anti-schizophrenic drug treatmentoften develop a syndrome that involves permanent damage of their abilityto control coordinated movement.

The foregoing studies have shown that the sigma binding site has thecharacteristics of 1) stereo-selectivity towards dextrorotatorybenzomorphan opiates and insensitivity for naloxone; 2) high affinityfor haloperidol and moderate to high affinity for phenothiazineantipsychotic drugs which are also known to be potent dopamine receptorblockers; and 3) insensitivity for dopamine and apomorphine. Thisintriguing drug selectivity profile calls for a thorough analysis of therole of sigma receptors in normal and abnormal brain function. In orderto do so, it is essential that a spectrum of highly selective and potentsigma receptor active compounds be available. This invention providessuch compounds and methods for identifying other drugs having suchactivity.

SUMMARY OF THE INVENTION

The invention relates to novel N,N'-disubstituted guanidines which bindto sigma receptor sites, especially those which do so selectively.

The invention also relates to a novel class of N,N'-disubstitutedguanidines which are radioactively tagged and which are useful forassaying in vitro the sigma receptor binding activity of organiccompounds.

The invention also relates to pharmacological compositions comprisingcertain of the aforesaid N,N'-disubstituted guanidines having sigmareceptor binding activity.

The invention also relates to a method for determining the sigmareceptor binding activity of organic compounds.

The invention also relates to an in vitro screening method for assayingcompounds having sigma receptor activity and utility as antipsychoticand antidepressant drugs.

The invention also relates to a method for treating abnormalpsychotic-like behavior in mammals, in particular, humans, andpharmacological compositions comprising N,N'-disubstituted guanidinecompounds which are efficacious in the treatment of such abnormalpsychotic-like behavior.

The invention also relates to a method of determining the relationshipof abnormal psychotic-like behavior in a mammal displaying such behaviorto sigma receptor system dysfunction.

The invention also relates to N,N-disubstituted guanidine pharmaceuticalcompositions comprising said N,N'-disubstituted guanidine compounds, andmethods for using same to treat hypertension.

The substituted guanidines of the invention have the Formula (I):##STR3## wherein R and R' are an alkyl group of at least 4 carbon atoms,a cycloalkyl group of at least 3 carbon atoms, a carbocyclic aryl groupof at least 6 carbon atoms, alkaryl or aralkyl of at least 6 carbonatoms and containing 1-3 separate or fused rings, or a heterocyclicring, and wherein each of R and R' may be substituted in 1-3 positions,or wherein R and R' together with the guanidine group to which they areattached form a saturated or unsaturated cyclic ring containing at least2 carbon atoms exclusive of the guanidine carbon atom, and wherein saidcyclic ring may be substituted with one or more alkyl groups of 1-6carbon atoms, carbocyclic aryl groups of at least 6 carbon atoms,cycloalkyl groups of 3-12 carbon atoms, or 1-2 fused aromatic rings, andfurther wherein said N,N'-disubstituted guanidine exhibits a highaffinity for the sigma receptor. Preferably, such N,N'-disubstitutedguanidines also exhibit antipsychotic and/or antihypertensive activityin an animal, for example, in an animal model.

In particular, the invention relates to N,N'-disubstituted guanidines ofthe Formula (I), above, wherein R and R' each are adamantyl, cyclohexylor a monocyclic carbocyclic aryl of at least 6 carbon atoms.

The invention also relates to substituted guanidines having the Formula(II): ##STR4## wherein X and Y are independently a branched or straightchain C₁ -C₁₂ alkylene or a branched or straight chain C₂ -C₁₂unsaturated alkylene or wherein one of X and Y is a single bond;

R and R' are independently hydrogen, a cycloalkyl group of at least 3carbon atoms, a carbocyclic aryl group of at least 6 carbon atoms,aralkyl of at least 6 carbon atoms and containing 1-3 separate or fusedrings, or a heterocyclic ring, and wherein each of R and R' may besubstituted in 1-3 positions, or wherein R and R' together with theguanidine group to which they are attached form a saturated orunsaturated cyclic ring containing at least 4 carbon atoms exclusive ofthe guanidine carbon atom, and wherein said cyclic ring may besubstituted with one or more alkyl groups of 1-6 carbon atoms,carbocyclic aryl groups of at least 6 carbon atoms, cycloalkyl groups of3-12 carbon atoms, or 1-2 fused aromatic rings. Preferably, saidN,N'-disubstituted guanidine exhibits a high affinity for the sigmareceptor.

The invention also relates to compounds having the formula: ##STR5##wherein n is 2, 3, 4 or 5;

X and Y are independently a single bond, a branched or straight chain C₁-C₁₂ alkylene or a branched or straight chain C₂ -C₁₂ alkylene;

R and R' are independently hydrogen, a cycloalkyl group of at least 3carbon atoms, a carbocyclic aryl group of at least 6 carbon atoms,aralkyl of at least 6 carbon atoms and containing 1-3 separate or fusedrings, a heterocyclic ring, and wherein each of R and R' may besubstituted in 1-3 positions, or wherein R and R' together with theguanidine group to which they are attached form a saturated orunsaturated cyclic ring containing at least 4 carbon atoms exclusive ofthe guanidine carbon atom, and wherein said cyclic ring may besubstituted with one or more alkyl groups of 1-6 carbon atoms,carbocyclic aryl groups of at least 6 carbon atoms, cycloalkyl groups of3-12 carbon atoms, or 1-2 fused aromatic rings; wherein said compoundexhibits a high affinity for the sigma receptor.

The invention also relates to tritiated derivatives of the above-listedN,N'-disubstituted guanidines wherein at least one of the ring carbonatoms of R and R' bears at least one tritium atom

The invention also relates to pharmaceutical compositions, in unitdosage form and adapted for systemic administration to a human being,which comprises, per unit dosage, an amount effective to alter the sigmabrain receptor-modulated activity of a human being displaying psychoticbehavior or suffering from chronic depression, of an N,N'-disubstitutedguanidine in its water-soluble protonated form which displaces in vitroN,N'-di-(4-[³ H]-2-methylphenyl)-guanidine bound to isolated mammalianbrain membrane.

The invention also relates to a method of determining the sigma brainreceptor binding activity of an organic compound which comprises thesteps of:

a) contacting in an aqueous medium a known amount of isolated mammalianbrain membrane which has sigma receptor-type binding activity, with amixture of (i) a tritium-labeled N,N'-disubstituted guanidine whichselectively binds sigma brain receptors, in a known amount capable ofbeing bound to the sigma receptors of that brain membrane; and (ii)varying known amounts of a water soluble organic compound to be assayedfor sigma receptor binding activity;

b) separating the brain membrane from the tritium labeled compound whichis not bound to the brain membrane in step a);

c) determining, from the molar relationship of the proportion of boundtritium labeled compound which is separated in step b) to the molaramount of the organic compound employed in step a), the sigma receptorbinding activity of that organic compound.

The invention also relates to a method of determining the relationshipof abnormal psychotic-like behavior in a mammal displaying such behaviorto sigma receptor dysfunction, which comprises administering thereto asigma brain receptor-modulating amount of a water-solubleN,N'-disubstituted guanidine which displaces in vitro N,N'-di-(4-[³H]-2-methylphenyl)-guanidine bound to mammalian brain membrane,effective to alter the sigma brain receptor-modulated mental activity ofthat mammal.

The invention also relates to a method of treating a human beingsuffering from chronic depression or a psychotic mental illnessassociated with hallucinations, e.g., schizophrenia, which comprisesadministering thereto a water soluble N,N'-disubstituted-guanidine whichis an antagonist to the sigma receptor binding activity of ahallucinogenic benzomorphan, and/or which displaces in vitroN,N'-di-(4-[³ H]-2-methylphenyl)-guanidine bound to mammalian brainmembrane, preferably a compound of Formulae (I) or (II), in an amounteffective to ameliorate the depression or hallucinations, respectively.

The invention also relates to the use of the N,N'-disubstitutedguanidines for the treatment of hypertension.

By the present invention, there is provided a means for identifyingcompounds which bind competitively and selectively to the sigma receptorsite. Accordingly, the invention provides compounds, pharmaceuticalcompositions, and the use of same for treatment of psychoses. Selectivesigma receptor binding is of particular value in reducing or eliminatingundesirable extrapyramidal side effects associated with presentantipsychotic medications. Further, these compounds are useful for thetreatment of hypertension.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

We have discovered that the disubstituted guanidines of this inventionhave-sigma receptor binding activity, as evidenced by their ability todisplace from guinea pig membrane binding sites [³H]-1,3-di-ortho-tolyl-guanidine (N,N'-di-(4-[³H]-2-methylphenyl)-guanidine ([³ H]-DTG]) which has the Formula (III):##STR6## binds reversibly, saturably, selectively and with high affinityto sigma receptor binding sites in guinea pig brain membrane homogenatesand slide-mounted rat and guinea pig brain sections. We have establishedthat (+)-[³ H]3-PPP binds to the same sites. Availability of theselective sigma ligands of this invention facilitates characterizationof sigma receptors in vivo and in vitro.

The preferred N,N'-disubstituted guanidines of this invention are thoseof the Formula (I): ##STR7## wherein R and R' each are an alkyl group ofat least 3 carbon atoms or carbocyclic aryl groups of at least 6 carbonatoms, e.g., R and R', which can be the same or different, are alkyl of4 or more carbon atoms, e.g., a 4 to 12, preferably a straight chainalkyl and more

carbon atom alkyl group, for example, butyl, isobutyl, tert-butyl, amyl,hexyl, octyl, nonyl and decyl; cycloalkyl of 3 to 12 carbon atoms, e.g.,cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl,1,4-methylene-cyclohexanyl, adamantyl, cyclopentylmethyl,cyclohexylmethyl, 1- or 2-cyclohexylethyl and 1-, 2- or3-cyclohexylpropyl; carbocyclic aryl, alkaryl or aralkyl, e.g., of up to18 carbon atoms and containing 1-3 separate or fused aromatic rings,e.g., phenyl, benzyl, 1- and 2-phenylethyl, 1-, 2-, or 3-phenylpropyl;o-, m- or p-tolyl, m,m'-dimethylphenyl, o-, m- or p-ethylphenyl,m,m'diethylphenyl, m-methyl-m' -ethylphenyl and o-propylphenyl,naphthyl, 2-naphthyl, biphenyl; and heterocyclic rings, e.g., 2- and4-pyridyl, pyrrolyl especially 2- and 3-N-methylpyrrolyl, 2- and3-furanyl, 2- and 3-thiophenyl, 2- and 3-benzofuranyl, 2-benzoxazolyl,pyrazinyl, pyrimidyl, 2-, 4- and 5- thiazolyl, 2-, 4- and 5- oxazolyl,2-, 4- and 5- imidazolyl, 2- and 3- indolyl, and 2- and 4-benzothiazolyl.

Additionally, 1, 2, 3 or more substituents which do not adversely affectthe activity of the N,N'-disubstituted guanidine moiety may be presenton one or both of the R and R' hydrocarbon groups thereof, e.g., alkylof 1-8 carbon atoms, e.g., methyl, ethyl; hydroxyalkyl of 1-8 carbonatoms; halo, e.g., chloro, bromo, iodo, fluoro; hydroxy; nitro; azido,cyano; isocyanato; amino; lower-alkylamino; di-lower-alkylamino;trifluoromethyl; alkoxy of 1-8 carbon atoms, e.g., methoxy, ethoxy andpropoxy; acyloxy, e.g., alkanoyloxy of 1-8 carbon atoms, e.g., acetoxyand benzoyl; amido, e.g., acetamido, N-ethylacetamido; carbamido, e.g.,carbamyl, N-methylcarbamyl, N,N'-dimethylcarbamyl; etc.

Especially preferred are compounds of Formula I wherein R and R' eachare phenyl groups, which need not necessarily be identical, substitutedwith one or more of the foregoing substituents, for example, in the o-,m- or p- position or the 2,2-, 2,4- or 3,5-position, when the phenylgroup is disubstituted or R is as herein defined and R' is adamantyl.Specific examples are those wherein R and R' both are phenyl or o-tolyl;R is o-tolyl and R' is p-bromo-o-tolyl, p-CF₃ -o-tolyl, p-iodo-o-tolyl,o-iodo-phenyl, p-azido-o-tolyl, cyclohexyl or adamantyl; and R is phenyland R' is p-bromo-o-tolyl, p-iodo-o-tolyl, m-nitro-phenyl oro-iodo-phenyl.

The highly active disubstituted guanidines of this invention, e.g., DTG,have substantially the same stereoconfiguration as (+)3-PPP with phenylaxial and with SKF 10,047 with the piperidine ring in a skew-boat formand N-allyl axial. This similarity in spacial configuration, i.e., asdemonstrated by computer modeling, of compounds having sigma receptorbinding activity provides a screening technique for predicting theprobable level of sigma receptor binding activity of otherN,N'-disubstituted guanidines. Computer assisted molecular modifying canbe used to determine the molecular similarity of the various species inthree dimensions.

Examples of those compounds which have been isolated and/or prepared andfound to possess the aforesaid in vitro [³ H]DTG displacement activityare N,N'-dibutylguanidine, N,N'-diphenylguanidine,N,N'-di-o-tolylguanidine, N,N'-di-(2-methyl-4-bromo-phenyl)guanidine,N,N'-di-(2-methyl-4-iodophenyl)guanidine,N-(2-methyl-azidophenyl)-N'-(2-methylphenyl)guanidine,N,N'-diadamantylguanidine, N-adamantyl-N'-(2-methylphenyl)guanidine,N-(2-iodophenyl)-N'-(2-methylphenyl)-guanidine,N-(2-methyl-4-nitrophenyl)-N'-(2-methylphenyl)guanidine,N,N'-di-(2,6-dimethylphenyl)guanidine,N-(2,6-dimethylphenyl)-N'-(2-methylphenyl)-N'-(2-methylphenyl)guanidine,N-(adamantyl)-N'-(cyclohexyl)guanidine, N,N'-di(cyclohexyl)guanidine,N-(2-iodophenyl)-N'-(adamantyl)guanidine,N-(2-methylphenyl)-N'-cyclohexyl-guanidine,N-adamantyl-N'-phenylguanidine, N-(o-tolyl)-N'-(o-iodophenyl)guanidine,N,N'-di-(p-bromo-o-methylphenyl)guanidine,N,N'-di-(m-n-propylphenyl)-guanidine,N-(o-tolyl)-N'-(p-nitro-o-tolyl)guanidine,N,N'-di-(1-tetralinyl)guanidine, N-(o-tolyl)-N'-(o-xylyl)guanidine,N,N'-di-(o-xylyl)guanidine, N,N'-di-(cyclohexyl)guanidine,N-(3,5-dimethyl-1-adamantanyl)-N'-(o-tolyl)guanidine,N-(3,5-dimethyl-1-adamantanyl)-N'-(o-iodophenyl)guanidine,N-(1-adamantyl)-N'-(o-nitrophenyl)guanidine,N,N'-di-((±)-endo-2-norbornyl)guanidine,N-(exo-2-isobornyl)-N'-(o-iodophenyl)guanidine,N,N'-di-(exo-2-norbornyl)guanidine,N-(exo-2-isobornyl)-N'-(o-tolyl)guanidine,N-(o-iodophenyl)-N'-(t-butyl)guanidine, N,N'-dibenzylguanidine,N-(adamant-1-yl)-N'-(o-isopropylphenyl)guanidine,N-(adamant-1-yl)-N'-(p-bromo-o-tolyl)guanidine,N-(cyclohexyl)-N'-(p-bromo-o-tolyl)guanidine, and N-(adamant-2-yl)-N'-(p-iodophenyl)guanidine.

Among the compounds tested to date, some of those having the highestsigma receptor binding activity are those of Formula I wherein one of Rand R' is adamantyl and the other is also adamantyl or o-substitutedphenyl. Therefore, the preferred compounds of this invention includethose wherein R and R¹ have those values, i.e., wherein the other of Rand R¹ is, e.g., o-lower alkyl phenyl, wherein alkyl is of 1-4 carbonatoms, e.g., CH₃, C₂ H₅, i-C₃ H₇, o-halophenyl wherein halo is Cl, Br, Ior F, o-nitro-o-amino, o-carbo-lower alkoxy, e.g., COOCH₃, o-amino,e.g., --CONH₂, o-sulfato, o-carboxy, o-acyl, e.g., acetyl, o-CF₃,o-sulfamido and o-lower-alkoxy, e.g., o-methoxy, phenyl or anotherphenyl group ortho substituted by any other substituent of a molecularweight less than 150.

Included in the substituted guanidines useful in the practice of thisinvention are those which have the Formula (I): ##STR8## wherein R andR' are an alkyl group of at least 3 carbon atoms, a cycloalkyl group ofat least 3 carbon atoms, a carbocyclic aryl group of at least 6 carbonatoms, alkaryl or aralkyl of at least 6 carbon atoms and containing 1-3separate or fused rings, or a heterocyclic ring, and wherein each of Rand R' may be substituted in 1-3 positions, or wherein R and R' togetherwith the guanidine group to which they are attached form a cyclic ringcontaining at least 2 carbon atoms exclusive of the guanidine carbonatom, and wherein said cyclic ring may be substituted with one or morealkyl groups of 1-6 carbon atoms, carbocyclic aryl groups of at least 6carbon atoms, cycloalkyl groups of 3-12 carbon atoms, or 1-2 fusedaromatic rings, and further wherein said N,N'-disubstituted guanidineexhibits a high affinity for the sigma receptor.

Preferred N,N'-disubstituted guanidines which are useful in the practiceof this invention are those wherein R and R', which need not beidentical, are an alkyl group of at least 3 carbon atoms or carbocyclicaryl groups of at least 6 carbon atoms, e.g., R and R', which can be thesame or different, are alkyl of 4 or more carbon atoms, e.g., a 4 to 12carbon atom, preferably a straight chain alkyl group and more preferablya 4 to 8 carbon atom alkyl group, for example, butyl, isobutyl,tert-butyl, amyl, hexyl, octyl, nonyl and decyl; cycloalkyl of 3 to 12carbon atoms, e.g., cyclopropyl, cyclopentyl, cyclohexyl, cycloheptyl,1,4-methylene-cyclohexane, adamantyl, cyclopentylmethyl,cyclohexylmethyl, 1- or 2-cyclohexylethyl and 1-, 2- or3-cyclohexylpropyl; carbocyclic aryl, alkaryl or aralkyl, e.g., of up to18 carbon atoms and containing 1-3 separate or fused aromatic rings,e.g., phenyl, benzyl, 1- and 2-phenylethyl, 1-, 2-, or 3-phenylpropyl;o-, m-, or p-tolyl, m,m'-dimethylphenyl, o-, m-, or p-ethylphenyl,m,m'-diethylphenyl, m-methyl-m'-ethylphenyl and o-propylphenyl,naphthyl, 2-naphthyl, and biphenyl, and heterocyclic aromatic ringsincluding pyridyl, pyrazinyl, pyrimidyl, furyl, pyrolyl, thienyl,thiazolyl, oxazolyl, imidazolyl, indolyl, and benzothiazolyl.

Additionally, 1, 2, 3 or more substituents which are chemically andphysiologically substantially inert compared to the guanidine group maybe present on the R and R' hydrocarbon groups, e.g., alkyl of 1-8 carbonatoms, e.g., methyl, ethyl; hydroxyalkyl of 1-8 carbon atoms; hydroxy;halo, e.g., chloro, bromo, iodo, fluoro; nitro; azido; cyano; isocyano;amino; lower-alkylamino; di-lower-alkylamino; trifluoromethyl; alkoxy of1-8 carbon atoms, e.g., methoxy, ethoxy and propoxy; acyloxy, e.g.,alkanoyloxy of 1-8 carbon atoms, e.g., acetoxy and benzoxy; amido, e.g.,acetamido, N-ethylacetamido; carbamido, e.g., carbamyl,N-methylcarbamyl, N,N'-dimethylcarbamyl; etc.

A preferred class of compounds of Formula I are those wherein R and R',which need not be necessarily identical, are phenyl or substitutedphenyl groups, cyclohexyl, norbornyl, adamant-1-yl and adamant-2-ylgroups. Substituted phenyl groups may have one or more of the foregoingsubstituents, for example, in the o-, m- or p-position or the o-, p- orm, m'-position, when the phenyl group is disubstituted, or R is asherein defined and R' is adamantyl.

Especially preferred N,N'-disubstituted guanidine compounds which havehigh binding to the sigma receptor includeN-(2-iodophenyl)-N'-(adamant-1-yl)guanidine (AdIpG, IC₅₀ =6.2 nM);N-(o-tolyl)-N'-(adamant-1-yl)guanidine (AdTG, IC₅₀ =7.6 nM);N,N'-di-(adamant-1-yl)guanidine (DAG, IC₅₀ =16.5 nM);N-cyclohexyl-N'-(2-methylphenyl)-guanidine (IC₅₀ =13 nM);N-(adamant-1-yl)-N'-cyclohexylguanidine (IC₅₀ =12.5 nM);N-(adamant-2-yl)-N'-(2-iodophenyl)guanidine (IC₅₀ =3.5 nM);N-(adamant-2-yl)-N'-(2-methylphenyl)guanidine (IC₅₀ =7.0 nM);N-(exo-2-norbornyl)-N'-(2-methylphenyl)guanidine (IC₅₀ =7.0 nM);N-((±)-endo-2-norbornyl)-N'-(2-methylphenyl)guanidine (IC₅₀ =6.0 nM);N-(exo-2-norbornyl)-N'-(2-iodophenyl)guanidine (IC₅₀ =4.0 nM);N-((±)-endo-2-norbornyl)-N'-(2-iodophenyl)guanidine (IC₅₀ =5.0 nM);N,N'-di-(o-tolyl)guanidine (IC₅₀ =32 nM);N-(o-tolyl)-N'-(o-iodophenyl)guanidine (IC₅₀ =21 nM);N,N'-di-(p-bromo-o-methylphenyl)-guanidine (IC₅₀ =37 nM);N,N'-di-(m-n-propylphenyl)guanidine (IC₅₀ =36 nM);N-(o-tolyl)-N'-(p-nitro-o-tolyl)guanidine (IC₅₀ =37 nM);N,N'-di-(1-tetralinyl)guanidine (IC₅₀ =58 nM);N-(o-tolyl)-N'-(o-xylyl)guanidine (IC₅₀ = 70 nM);N,N'-di-(o-xylyl)guanidine (IC₅₀ =90 nM); N,N'-di-(cyclohexyl)guanidine(IC₅₀ =71 nM); N-(3,5-dimethyladamantan-1-yl)-N'-(o-tolyl)guanidine(IC₅₀ =15 nM); N-(3,5-dimethyl-1-adamantanyl)-N'-(o-iodophenyl)guanidine(IC₅₀ =16 nM); N-(1-adamantyl)-N'-(o-nitrophenyl)guanidine (IC₅₀ =30nM); N,N'-di-((±)-endo-2-norbornyl)guanidine (IC₅₀ =16 nM);N-(exo-2-isobornyl)-N'-(o-iodophenyl)guanidine (IC₅₀ =18 nM);N,N'-di-(exo-2-norbornyl)guanidine (IC₅₀ =22 nM);N-(exo-2-isobornyl)-N'-(o-tolyl)guanidine (IC₅₀ =25 nM);N-(o-iodophenyl)-N'-(t-butyl)guanidine (IC₅₀ =20 nM);N,N'-dibenzylguanidine (IC₅₀ =90 nM);N-(adamant-1-yl)-N'-(o-isopropylphenyl)guanidine (IC₅₀ =24 nM);N-(adamant-1-yl)-N'-(p-bromo-o-tolyl)guanidine (IC₅₀ =2.7 nM);N-(cyclohexyl)-N'-(p-bromo-o-tolyl)-guanidine (IC₅₀ =5.5 nM); andN-(adamant-2-yl)-N'-(o-iodophenyl)-guanidine (IC₅₀ =5.2 nM).

A preferred class of N,N-disubstituted guanidines have saturated orunsaturated alkylene groups substituted between the nitrogen of theguanidine and a cyclic group. Such N,N'-disubstituted guanidines havethe Formula (II): ##STR9## wherein X and Y are independently a branchedor straight chain C₁ -C₁₂ alkylene or a branched or straight chain C₂-C₁₂ alkylene or wherein one of X and Y is a single bond;

R and R' are independently hydrogen, a cycloalkyl group of at least 3carbon atoms, a carbocyclic aryl group of at least 6 carbon atoms,alkaryl or aralkyl of at least 6 carbon atoms and containing 1-3separate or fused rings, a heterocyclic ring, and wherein each of R andR' may be substituted in 1-3 positions, or wherein R and R' togetherwith the guanidine group to which they are attached form a saturated orunsaturated cyclic ring containing at least 4 carbon atoms exclusive ofthe guanidine carbon atom, and wherein said cyclic ring may besubstituted with one or more alkyl groups of 1-6 carbon atoms,carbocyclic aryl groups of at least 6 carbon atoms, cycloalkyl groups of3-12 carbon atoms, or 1-2 fused aromatic rings, and further wherein saidN,N'-disubstituted guanidine exhibits a high affinity for the sigmareceptor.

Preferably, X and Y are C₁ -C₄ alkylene groups.

A second preferred class of N,N'-disubstituted guanidines have thefollowing Formula (III): ##STR10## wherein n is 2, 3, 4 or 5;

X and Y are independently a single bond, a branched or straight chain C₁-C₁₂ alkylene or a branched or straight chain C₂ -C₁₂ alkylene;

R and R' are independently hydrogen, a cycloalkyl group of at least 3carbon atoms, a carbocyclic aryl group of at least 6 carbon atoms,aralkyl of at least 6 carbon atoms and containing 1-3 separate or fusedrings, a heterocyclic ring, and wherein each of R and R' may besubstituted in 1-3 positions, or wherein R and R' together with theguanidine group to which they are attached form a saturated orunsaturated cyclic ring containing at least 4 carbon atoms exclusive ofthe guanidine carbon atom, and wherein said cyclic ring may besubstituted with one or more alkyl groups of 1-6 carbon atoms,carbocyclic aryl groups of at least 6 carbon atoms, cycloalkyl groups of3-12 carbon atoms, or 1-2 fused aromatic rings, and further wherein saidN,N'-disubstituted guanidine exhibits a high affinity for the sigmareceptor.

Preferably, R and R' are o-tolyl, X and Y are single bonds and n is 2,e.g., N,N'-di(o-tolyl)-2-iminoimidazolidine.

The level of sigma receptor activity of the disubstituted guanidines canalso be determined in vivo in a discriminative stimulus property testemploying rats trained to discriminate between intraperitonealinjections of cyclazocine (2.0 mg/kg) and saline in a discrete-trialavoidance paradigm with sessions of 20 trials each. For example,ditolylguanidine (DTG) and diphenylguanidine (DPG) were fullysubstitutable for cyclazocine at the same concentrations. (Holtzman, S.G., Emery University, Atlanta, Ga., private communication.)

Although the discussion hereinafter of the experiments below relates tocertain of these selective sigma receptor ligands, viz., theN,N'-disubstituted guanidines of Table I below, the activity and utilityof that compound apply comparably to the other disubstituted guanidineswhich compete with and displace in vitro N,N'-di-(4-[³H]-2-methylphenyl)-guanidine bound in vitro to isolated guinea pig brainmembrane.

In carrying out the sigma receptor binding activity measurement methodof this invention, a known amount of a mammalian brain membrane, e.g.,human or other primate, porcine, rodent, e.g., rat or guinea pig, whichhas SKF 10,047 and like psychotomimetic benzomorphan binding activity iscontacted in a suitable aqueous vehicle, e.g., physiological salinesolution, with a mixture, usually in a solution in a suitable aqueousvehicle of (i) a tritium-labeled N,N'-di-substituted guanidine of thisinvention having sigma receptor binding activity, in an amount capableof being fully bound to the abovesaid amount of membrane and (ii) awater soluble organic compound whose sigma receptor activity is to beassayed, in known amounts, sufficiently varied to obtain a dose-responsecurve. The techniques for obtaining a dose-response curve are standardand well known to those skilled in the art. Typically, one could employmolar amounts varying as much as from 10⁻⁴ to 10⁴ of the molar amount ofthe tritium labeled compound present in the mixture, e.g., employingfrom 10 to 120 and preferably 30 to 90 such mixtures.

If the organic compound being assayed has sigma receptor bindingactivity, a portion of the tritium labeled compound which, in theabsence of the organic compound would bind to the membrane remainsunbound and is thus separable from the membrane. The amount whichremains unbound is proportional to the sigma receptor binding activityof the organic compound and the molar ratio thereof in the mixture tothe tritium labeled compound.

The two compounds can be employed at any convenient collectiveconcentration, e.g., from 10⁻⁸ to 10³ mM.

In the next step, the membrane is separated from and washed until freeof the solution in which step (a) is conducted. In the next step, theamount of tritium labeled compound which is thus separated from themembrane is determined, e.g., by measuring the collective radioactivitylevel of the separated solution and wash water and comparing thatradioactivity to that obtained when the foregoing steps are conductedwith the same amount of tritium-labeled N,N'-di-substituted guanidine inthe absence of the organic compound.

In the next step of the method, the activity of sigma receptor bindingactivity of the organic compound is determined from the dose responsecurve thus obtained.

All of the foregoing steps are conventional and have been employed inthe prior art with other types of [³ H-labeled compounds having sigmareceptor binding activity. The method of this invention is, however,unique in that the tritium-labeled N,N'-disubstituted guanidines of thisinvention are highly selective to binding by the sigma receptors andtherefore will not compete with organic compounds which bind to otherbrain receptors.

In carrying out the method of treatment aspect of this invention, e.g.,treating a human being suffering from a psychotic mental illnessassociated with hallucinations there is administered thereto awater-soluble N,N'-disubstituted guanidine which is an antagonist to thesigma receptor binding activity of a hallucinogenic benzomorphan, in anamount effective to ameliorate the hallucinations. Preferably, theguanidine is a compound of Formulae I, II or III wherein R and R' eachis an alkyl group of at least 4 carbon atoms, a cycloalkyl group of 3 to12 carbon atoms or a carbocyclic aryl group of at least 6 carbon atoms.In preferred aspect, the human being is schizophrenic; in anotherpreferred aspect, the compound is N,N'-di-(2-methylphenyl)-guanidine,N-(adamantyl)-N'-(cyclohexyl)guanidine,N-adamantyl-N'-(2-methylphenyl)guanidine,N-(1-adamantyl)-N'-(o-iodophenyl)guanidine,N-(2-adamantyl)-N'-(o-iodophenyl)guanidine,N-cyclohexyl-N'-(2-methylphenyl)guanidine,N,N'-di-(cyclohexyl)guanidine, N,N'-di-(2-adamantyl)guanidine,N,N'-di-(m-n-propylphenyl)guanidine,N-(o-tolyl)-N'-(p-nitro-o-tolyl)guanidine,N,N'-di-(1-tetralinyl)guanidine, N-(o-tolyl)-N'-(o-xylyl)guanidine,N,N'-di-(o-xylyl)guanidine,N-(3,5-dimethyladamantan-1yl)-N'-(o-tolyl)guanidine,N-(3,5-dimethyladamantan-1-yl)-N'-(o-iodophenyl)guanidine,N-(1-adamantyl)-N'-(o-nitrophenyl)guanidine, (+) and(-)N-(exo-2-norbornyl)-N'-(2-iodophenyl)guanidine, (+) and(-)N-(endonorbornyl)-N'-(o-tolyl)guanidine, (+) and(-)N-(exonorbornyl)-N'-(o-tolyl)guanidine, (+) and(-)N,N'-di(endonorbornyl)guanidine, (+) and(-)N-(exoisobornyl)-N'-(o-iodophenyl)guanidine, (+) and(-)N,N'-di-(exonorbornyl)guanidine,N-(o-iodophenyl)-N'-(t-butyl)-guanidine, N,N'-dibenzylguanidine,N-(adamant-1-yl)-N'-(o-isopropylphenyl)guanidine,N-(adamant-1-yl)-N'-(p-bromo-o-tolyl)guanidine,N-(cyclohexyl)-N'-(p-bromo-o-tolyl)guanidine,N-(adamant-2-yl)-N'-(p-iodophenyl)guanidine,N,N'-di(o-methylbenzyl)guanidine andN,N'-di(1-adamantanemethyl)guanidine; or a corresponding compoundbearing 1, 2, 3 or more additional or other substituents on one or bothhydrocarbon groups, e.g., alkyl of 1-8 carbon atoms, e.g., methyl-,ethyl; halo, e.g., chloro, bromo, iodo, fluoro; nitro; azido; cyano;isocyanato; amino; lower-alkylamino; di-lower-alkylamino;trifluoromethyl; alkoxy of 1-8 carbon atoms, e.g., methoxy, ethoxy andpropoxy; acyloxy, e.g., alkanoyloxy of 1-8 carbon atoms, e.g., acetoxyand benzoyl; amido, e.g., acetamido, N-ethylacetamido; carbamido, e.g.,carbamyl, N-methylcarbamyl, N, N'-dimethyl carbamyl; etc.

N,N'-disubstituted guanidines, e.g., of Formulae I and II, can act in anagonistic, antagonistic or inverse agonistic manner in relation to theprototypical sigma benzomorphans. Those which act as antagonists cantherefore be expected to affect pupil size, heart rate and mentation ina direction opposite that caused by benzomorphans which can bedetermined by standard tests in laboratory animals. The type and levelof activity for a given dosage of each compound can be conventionallydetermined by routine experimentation using well known pharmacologicalprotocols for each of the activities; the corresponding indicationstreatable at that dosage will be well known to skilled workers based onthe pharmacological results. The compounds of this invention areparticularly noteworthy for their antipsychotic activity to treatpsychotic conditions, e.g., schizophrenia, by analogy to the knownagents prolixin and haloperidol and for diagnosing sigma receptorintoxicated conditions.

The [³ H]DTG of this invention is useful as a screening tool forcompounds, such as the disubstituted guanidines of this invention, whichare selective ligands for the sigma receptor binding site. As such, theyare useful for screening for compounds useful for the diagnosis andtreatment of sigma receptor mediated hallucinogenic mental disorders.For example, such a compound which is an agonist to a putative naturalligand will temporarily exacerbate such a mental disorder which is theresult of an overabundance of the endogenous ligand and will amelioratea mental disorder which is the result of an abnormal insufficiency ofthe natural ligand. The converse occurs when the disubstituted guanidineis an antagonist to the putative endogenous ligand. In either case, thetemporary alteration of the mental disorder by the administered ligandconfirms that it is a sigma receptor associated disease, therebyeliminating other possible causes thereof, e.g., chemical toxicity, andfacilitating the treatment thereof.

[³ H]-DTG also binds to human brain membrane receptors with highaffinity as determined in our laboratory. Therefore another use of [³H]-DTG is to explore the neurochemistry of mental disease by measuringthe fluctuations in receptor density or function in post-mortem tissueof patients manifesting psycho- or neuropathology as contrasted withtissue from normals (unaffected controls). This topic can be studied byboth receptor binding assays and autoradiography.

The N,N'-disubstituted guanidines can readily be prepared byconventional chemical reactions, e.g., when R and R' are the same, byreaction of the corresponding amine with cyanogen bromide. Other methodswhich can be employed include the reaction of an amine with a preformedalkyl or aryl cyanamide. See Safer, S. R., et al., J. Org. Chem. 13:924(1948). This is the method of choice for producing N,N'-disubstitutedguanidines in which the substituents are not identical. For a recentsynthesis of unsymmetrical guanidines, see G. J. Durant et al., J. Med.Chem. 28:1414 (1985), and C. A. Maryanoff et al., J. Org. Chem. 51:1882(1986), incorporated by reference herein.

Included as well in the present invention are pharmaceuticalcompositions comprising an effective amount of the N,N'-disubstitutedguanidines in combination with a pharmaceutically acceptable carrier.

The N,N'-disubstituted guanidines and the pharmaceutical compositions ofthe present invention may be administered by any means that achievetheir intended purpose. For example, administration may be byparenteral, subcutaneous, intravenous, intramuscular, intra-peritoneal,transdermal, or buccal routes. Alternatively, or concurrently,administration may be by the oral route. The dosage administered will bedependent upon the age, health, and weight of the recipient, kind ofconcurrent treatment, if any, frequency of treatment, and the nature ofthe effect desired.

Compositions within the scope of this invention include all compositionswherein the N,N'-disubstituted guanidine is contained in an amount whichis effective to achieve its intended purpose. While individual needsvary, determination of optimal ranges of effective amounts of eachcomponent is with the skill of the art. Typically, theN,N'-disubstituted guanidine compounds may be administered to mammals,e.g. humans, orally at a dose of 0.0025 to 15 mg/kg, or an equivalentamount of the pharmaceutically acceptable salt thereof, per day of thebody weight of the mammal being treated. Preferably, about 0.01 to about10 mg/kg is orally administered to treat or prevent such disorders. Forintramuscular injection, the dose is generally one-half of the oraldose. For example, for treatment or prevention of psychosis, a suitableintramuscular dose would be about 0.0025 to about 15 mg/kg, and mostpreferably, from about 0.01 to about 10 mg/kg.

The unit oral dose may comprise from about 0.25 to about 400 mg,preferably about 0.25 to about 100 mg of the N,N'-disubstitutedguanidine compound. The unit dose may be administered one or more timesdaily as one or more tablets each containing from about 0.10 to about300, conveniently about 0.25 or 50 mg of the N,N'-disubstitutedguanidine compound or its solvates.

In addition to administering the compound as a raw chemical, thecompounds may be administered as part of a pharmaceutical preparationcontaining suitable pharmaceutically acceptable carriers comprisingexcipients and auxiliaries which facilitate processing of the compoundsinto preparations which can be used pharmaceutically. Preferably, thepreparations, particularly those preparations which can be administeredorally and which can be used for the preferred type of administration,such as tablets, dragees, and capsules, and also preparations which canbe administered rectally, such as suppositories, as well as suitablesolutions for administration by injection or orally, contain from about0.01 to 99 percent, preferably from about 0.25 to 75 percent of activecompound(s), together with the excipient.

The pharmaceutical preparations of the present invention aremanufactured in a manner which is itself known, for example, by means ofconventional mixing, granulating, dragee-making, dissolving, orlyophilizing processes. Thus, pharmaceutical preparations for oral usecan be obtained by combining the active compounds with solid excipients,optionally grinding the resulting mixture and processing the mixture ofgranules, after adding suitable auxiliaries, if desired or necessary, toobtain tablets or dragee cores.

Suitable excipients are, in particular, fillers such as saccharides, forexample lactose or sucrose, mannitol or sorbitol, cellulose preparationsand/or calcium phosphates, for example tri-calcium phosphate or calciumhydrogen phosphate, as well as binders such as starch paste, using, forexample, maize starch, wheat starch, rice starch, potato starch,gelatin, tragacanth, methyl cellulose, hydroxypropylmethylcellulose,sodium carboxymethylcellulose, and/or polyvinyl pyrrolidone. If desired,disintegrating agents may be added such as the above-mentioned starchesand also carboxymethyl-starch, cross-linked polyvinyl pyrrolidone, agar,or alginic acid or a salt thereof, such as sodium alginate. Auxiliariesare, above all, flow-regulating agents and lubricants, for example,silica, talc, steric acid or salts thereof, such as magnesium stearateor calcium stearate, and/or polyethylene glycol. Dragee cores areprovided with suitable coatings which, if desired, are resistant togastric juices. For this purpose, concentrated saccharide solutions maybe used, which may optionally contain gum arabic, talc, polyvinylpyrrolidone, polyethylene glycol and/or titanium dioxide, lacquersolutions and suitable organic solvents or solvent mixtures. In order toproduce coatings resistant to gastric Juices, solutions of suitablecellulose preparations such as acetylcellulose phthalate orhydroxypropymethyl-cellulose phthalate, are used. Dye stuffs or pigmentsmay be added to the tablets or dragee coatings, for example, foridentification or in order to characterize combinations of activecompound doses.

Other pharmaceutical preparations which can be used orally includepush-fit capsules made of gelatin, as well as soft, sealed capsules madeof gelatin and a plasticizer such as glycerol or sorbitol. The push-fitcapsules can contain the active compounds in the form of granules whichmay be mixed with fillers such as lactose, binders such as starches,and/or lubricants such as talc or magnesium stearate and, optionally,stabilizers. In soft capsules, the active compounds are preferablydissolved or suspended in suitable liquids, such as fatty oils, orliquid paraffin. In addition, stabilizers may be added.

Possible pharmaceutical preparations which can be used rectally include,for example, suppositories, which consist of a combination of the activecompounds with a suppository base. Suitable suppository bases are, forexample, natural or synthetic triglycerides, or paraffin hydrocarbons.In addition, it is also possible to use gelatin rectal capsules whichconsist of a combination of the active compounds with a base. Possiblebase materials include, for example, liquid triglycerides, polyethyleneglycols, or paraffin hydrocarbons.

Suitable formulations for parenteral administration include aqueoussolutions of the active compounds in water-soluble form, for example,water-soluble salts. In addition, suspensions of the active compounds asappropriate oily injection suspensions may be administered. Suitablelipophilic solvents or vehicles include fatty oils, for example, sesameoil, or synthetic fatty acid esters, for example, ethyl oleate ortriglycerides. Aqueous injection suspensions may contain substanceswhich increase the viscosity of the suspension include, for example,sodium carboxymethyl cellulose, sorbitol, and/or dextran. Optionally,the suspension may also contain stabilizers.

The characterization of sigma receptors in vitro has been difficultbecause of the lack of selective drug ligands. Most benzomorphan opiatescross-react with other (mu, delta, kappa), opioid receptors and aretherefore of only limited value for characterizing and isolatingreceptors. Pasternak et al., J. Pharmacol. Exo. Ther. 219:192-198(1981); Zukin, R. S., et al., Mol. Pharm. 20:246-254 (1981); and Tam, S.W., Eur. J. Pharmacol. 109:33-41 (1985). [³ H]DTG binds specifically andwith high affinity to a single class of binding sites in guinea pigbrain membranes. The binding characteristics and the drug specificityprofile of these sites are concordant with those proposed for the sigmareceptor, including 1) naloxone insensitivity and stereoselectivity fordextrorotatory isomers of benzomorphan opiates such as (+)SKF 10,047,(+)cyclazocine and (+)pentazocine; 2) high affinity for haloperidol andcertain phenothiazine antipsychotic drugs; 3) stereoselectivity for(-)butaclamol; and 4) insensitivity to dopamine and apomorphine. [³H]-DTG is one of only two known tritiated

compounds that are selective for the sigma site. The other, (+)[³H]3-PPP, originally proposed to be a dopamine autoreceptor agonist, hasrecently been shown to be selective for sigma sites in rat brainmembrane binding assays. Largent et al. (1984), supra. Our experimentsconfirm these findings in the guinea pig and show that [³ H]DTG and(+)[³ H]3-PPP have virtually identical receptor binding characteristicsand drug selectivity profiles. Previous studies have shown that sigmasites can also be labeled with (+)[³ H]SKF 10,047, (+)[³H]-ethylketazocine and with (±)[³ H]SKF 10,047. However, these ligandsare not selective for the sigma site and require the presence ofappropriate drugs in the binding assays to mask cross-reacting non-sigmabinding sites.

[³ H]DTG has a number of advantages as a sigma ligand. It is highlyselective for the sigma site (unlike [³ H]SKF 10,047 and (+)[³H]ethylketazocine), it has a high degree of specific binding (90-97% oftotal binding) and it has a relatively simple chemical structure that isnot chiral (unlike (+)[³ H]3-PPP and the benzomorphan opiates). Thesecharacteristics make it a good starting compound for the synthesis ofanalogs for structure-activity studies and for the design ofirreversible (after photolysis) sigma receptor ligands, e.g., compoundsof Formulae I and II wherein at least one of R and R' isazido-substituted carbocyclic aryl.

The sigma site labeled with [³ H]DTG is clearly not related toconventional (mu, delta, kappa) opioid receptors as it is naloxoneinsensitive and shows stereoselectivity for dextrorotatory isomers ofbenzomorphan drugs. This is a reversed stereoselectivity compared tonaloxone-sensitive opioid receptors which are selective for levorotatoryisomers of opiates. Sigma receptors should therefore not be referred toas sigma "opioid" receptors. The drug selectivity of sigma sites fordextrorotatory isomers of psychotomimetic opiates does, however,correlate well with the pharmacological profile of dextrorotatory versuslevorotatory opiates in animal tests designed to differentiate betweenconventional opioid receptor activity and sigma (behavioral) activity ofbenzomorphan drugs. Cowan, A., Life Sci. 28:1559-1570 (1981); Brady, K.T., et al., Science 215:178-180 (1982); and Khazan, N., et al.,Neuropharmacol. 23:983-987 (1984).

Autoradiography studies using [³ H]DTG visualize the sigma site inslide-mounted rodent brain sections and confirm that sigma sites aredifferent from mu, delta, and kappa opioid receptors as the distributionof [³ H]DTG binding is rather distinct from the distribution of mu,delta, kappa opioid receptors. The anatomical distribution of [³ H]DTGbinding sites is, however, very similar if not identical to thedistribution of [³ H]3-PPP binding sites, further confirming that thetwo radioligands label identical binding sites. The high affinity of the[³ H]DTG binding site for haloperidol and for certain phenothiazineantipsychotics (TABLE I) which are also dopamine D₂ receptor antagonistsraises the question as to the relation of sigma receptors to dopamine D₂receptors. The results presented show that the [³ H]DTG site is clearlydistinct from dopamine D₂ receptors, because the autoradiographicdistribution of dopamine receptor is dissimilar and because dopamine,apomorphine and many other dopamine receptor ligands do not interactwith the [³ H]DTG binding site.

Furthermore the sigma site labeled with [³ H]DTG is stereoselective for(-)butaclamol which is a reversed stereoselectivity compared to thedopamine D₂ receptors which are stereoselective for (+)butaclamol.

The haloperidol-sensitive sigma site labeled with [³ H]DTG was found tohave a moderate affinity for the potent hallucinogen PCP in competitionexperiments. This is in agreement with findings by others who use (+)[³H]SKF 10,047, (±)[³ H]SKF 10.047 or (±)-[³ H]3-PPP to label sigma sites.In PCP receptor binding assays, however, [³ H]-PCP labeled predominantly(but not exclusively) a haloperidol-insensitive PCP binding site, termedPCP/sigma opiate receptor by Zukin and colleagues, Zukin et al. (1981,1986), supra, which is separate from the haloperidol-sensitive sigmasite labeled with [³ H]DTG or (+)[³ H]3-PPP. In contrast, [³ H]DTGappears to label exclusively the haloperidol sensitive sigma site, sinceall specific binding is displaceable by haloperidol and the anatomicaldistribution of [³ H]DTG binding is distinct from the distribution ofPCP receptors. Furthermore, unlabeled DTG is virtually inactive in a [³H]-PCP binding assay (S. William Tam, E. I. DuPont De Nemours & Co.,Wilmington, Del., personal communication). There is some controversy asto which of the two binding sites is responsible for causing thebehavioral effects of PCP and psychotomimetic benzomorphan opiates andwould therefore correspond to the sigma receptor postulated by Martin etal. (1976), supra, Zukin and his collaborators have argued that thebehavioral effects of both PCP and psychotomimetic benzomorphan opiatesare mediated by the haloperidol-insensitive PCP site, to whichbenzomorphan opiates bind with moderate affinity. Largent et al. (1986),supra, cited circumstantial evidence suggesting that it is equallylikely that the behavioral effects of both PCP and psychotomimeticopiates are mediated through the haloperidol sensitive sigma site. As [³H]DTG exclusively labels the haloperidol sensitive sigma site and doesnot interact significantly with the haloperidol-insensitive PCP site,behavioral studies using DTG or other substituted guanidines of thisinvention as prototypical sigma ligands, taking into account of whetherthey are agonists or antagonists (see below), should resolve this issue.

Perhaps the most important aspect of the findings on the drugspecificity of sigma sites that have emerged from this and other studiesis that they interact with certain very potent antipsychotic drugs(haloperidol, phenothiazines) that are used clinically to treatschizophrenia. This intriguing drug selectivity profile facilitatesstudies aimed at investigating the role of sigma receptors inantipsychotic drug action and abnormal brain function. The availabilityof DTG and like N,N'-disubstituted guanidines as a selective sigmaligand should serve to facilitate such studies.

The compounds of this invention have highly selective affinity for thesigma receptor. Consequently, they may have some of the activities ofthe benzomorphans, i.e., those produced by binding to thehaloperidol-sensitive sigma receptor but not those produced by thebinding of benzomorphans to other non-sigma receptors. For instance,benzomorphans may act at sigma receptors to cause mydriasis andtachycardia and pronounced psychotomimetic effects. DTG is therefore aneffective tool to demonstrate the physiological effects mediated by thesigma receptor which, to date, have been obscured by cross-reactivity ofbenzomorphans with non-sigma receptors. Additionally, at least some ofthe compounds of Formulae I and II, e.g., N,N'-diphenyl andN,N'-di-o-tolyl-guanine, are antagonists of the sigma receptors in thenerve terminals in the mouse vas deferens, where sigma receptorsstimulate noradrenaline release (a phenomena discovered by us and whichprovides a new screening test for CNS-stimulants and depressants), andthus are blood pressure lowering (anti-hypertensive) agents.

The compounds of this invention are particularly valuable in thetreatment of humans afflicted with a psychotic disease, e.g.,schizophrenia, or with chronic hypertension. In this regard, they can beemployed in substantially the same manner as known antipsychotic agentsand anti-hypertensive agents, respectively.

It will be appreciated that the actual preferred amounts of activecompounds used will vary according to the specific compound beingutilized, the particular compositions formulated, the mode ofapplication, and the particular site of administration, as well as theage, general health, and concurrent treatment of the patient. Optimaladministration rates for a given protocol of administration can bereadily ascertained by those skilled in the art using conventionaldosage determination tests conducted with regard to the foregoingguidelines.

The sigma receptor binding activity of N,N'-di-o-tolyl-guanidine (DTG)was discovered during studies on the purification and characterizationof an endogenous sigma receptor ligand. In the initial phases of thiswork numerous extraction solvents were tested for their suitability toextract endogenous sigma receptor ligand from cow brains. Certainextraction solvents (particularly acetone) contained an unidentifiedmaterial that potently displaced (+)-[³ H]SKF 10,047 from guinea pigbrain membrane binding sites. A receptor binding characterization of thematerial revealed that the binding activity was competitive, reversibleand rather potent. Because of the potent sigma receptor bindingproperties of three compounds that were found in these solvents, thesechemicals were purified to homogeneity using various reverse phase HPLCprocedures and their structure determined. Their structure wasdetermined by a combination of different methods including highresolution mass spectroscopy, nuclear magnetic resonance andUV-spectrophotometry. One of the three sigma receptor ligands proved tobe 1,3-di-o-tolyl-guanidine (DTG).

After its structural characterization, synthetic DTG was tested in the(+)-[³ H]SKF 10,047 binding assay and was found to displace (+)-[³ H]SKF10,047 from its brain membrane binding sites with a Kd of 70 nM. Thedisplacement was competitive and fully reversible.

Two other compounds were isolated and characterized and concluded to bedi-phenyl-guanidine (DPG) and dibutyl-guanidine (DBG). Both compoundswere active in the (+)-[³ H]SKF 10,047 binding assay.

Because of the high potency of DTG and related disubstituted guanidinesto displace (+)-[³ H]-SKF 10,047 from its binding sites it was decidedto synthesize a tritium labeled derivative of DTG. To do so,N,N'-di-(2-methyl-4-bromo-phenyl)-guanidine was subjected to catalyticreduction with tritium gas, which replaced the two bromine atoms withtritium atoms to produce N,N'-di(p-[³ H]-o-tolyl)-guanidine, asdescribed below.

Without further elaboration, it is believed that one skilled in the artcan, using the preceding description, utilize the present invention toits fullest extent. The following preferred specific embodiments are,therefore, to be construed as merely illustrative, and not limitative ofthe remainder of the disclosure in any way whatsoever. The entire textof all applications, patents and publications, if any, cited above andbelow are hereby incorporated by reference.

EXAMPLES

In the foregoing and in the following examples, all temperatures are setforth uncorrected in degrees Celsius and unless otherwise indicated, allparts and percentages are by weight.

Preparations

General Procedures. Melting points are uncorrected. NMR spectra wererecorded on a General Electric QE-300 spectrometer, operating at 300MHz. Chemical shifts (δ) are given in ppm using the residual protonsignal of the deuterated solvent as reference (CHD₂ OD δ3.300, CHCl₃δ7.260, HDO δ4.80), or the ¹³ C signal of the solvent (CD₃ OD δ49.00,CDCl₃ δ77.00). All solvents were reagent grade quality. Where drysolvents were needed, these were distilled from CaH₂ or Na before use.

Adamantan-1-ylcyanamide was prepared from the amine with cyanogenbromide in Et₂ O, as previously described by Geluk, N. W., et al., J.Med. Chem. 12:712-716 (1969). (2-Methylphenyl)cyanamide was preparedsimilarly.

N,N'-Di-(adamantan-1-yl)guanidine hydrochloride was prepared accordingto the procedure of Geluk et al., supra,

EXAMPLE 1 N,N'-Di-(4-bromo-2-methylphenyl)-guanidine (4-Br-DTG)

To a stirred solution of cyanogen bromide (846 mg, 8.06 mmol) indistilled water (70 ml) was added in small portions 2.997 g (16.11 mmol)of 4-bromo-2-methylaniline (Aldrich, recrystallized from etherpentane).A white precipitate formed during the addition. The mixture was stirredat 80° C. for 4 h. Upon cooling at 0° C. for 12 h, a sticky yellow oilseparated out and was discarded. The clear aqueous phase wasconcentrated to about 30 ml. The white precipitate which formed wasredissolved by heating the mixture. This was then set aside at 4° C. for12 h. Filtration gave 430 mg of white solid. A 200-mg portion wasdissolved in 10 ml of hot water and treated with 5 ml of 10 KOHsolution. The mixture was extracted with CHCl₃ and the extract waswashed with brine and then dried (MgSO₄). Evaporation of the solventgave 171 mg of a brown solid which was crystallized from CHCl₃, giving120 mg (8%) 4-Br-DTG as small white needles: mp 209°-210°; NMR (300 MHz,CD₃ OD, TMS) δ2,24 (s, 3), 7.12-7.25 (AB, 2, J=8 Hz), 7.35 (s,I); IR(KBr) 3460, 3340, 1630 cm⁻¹. Analysis calculated for C₁₅ H₁₅ N₃ Br₂ : C,45.37; H, 3.81; N, 10.58. Found: C, 45.34; H, 3.56; N, 10.50.

EXAMPLE 2 [³ H]-N,N'-di-ortho-tolyl-guanidine ([³ H] DTG)

Twenty-five mg (0.1 mmol) of the thus-produced 4-Br-DTG were submittedto Amersham Corporation (Arlington Heights, Ill.) for catalyticreduction in the presence of 20 Ci of [³ H]-gas. Two mCi portions of thecrude, radioactive product in 0.2 ml/each of 25% ethanol were purifiedby reverse phase high performance liquid chromatography (RP-HPu) on aVydac TP218 octadecasilica column using a CH₃ OH gradient (0-35% in 60minutes) in 0.1% trifluoroacetic acid for elution. Flow rate was 1ml/min. One minute fractions were collected. Aliquots of the fractionswere diluted 100 fold and 10 ul aliquots of the diluted fractionscorresponding to 0.1 ul of the original fractions were dissolved in 10ml scintillation fluid and counted in a scintillation spectrometer. Theequipment consisted of 2 Waters HPLC pumps, and automated electronicgradient controller and a Kratos variable wave length spectrophotometer.The radioactivity eluted as a major symmetrical peak coinciding with amajor, symmetrical UV (220 nm) absorbing peak at 41 minutes. This is thesame elution time at which authentic, unlabeled DTG emerges from thecolumn in this RP HPLC system. The specific activity of [³ H]DTG wasfound to be 52 Ci/mmol based on the amount of DTG under the major UVabsorbing peak as determined by quantitative UV-spectrophotometry andthe amount of radioactivity associated with this peak as determined byquantitative liquid scintillation spectrometry.

Following this procedure, or one of another conventional labellingsynthetic techniques well known in the art, the tritium labeled versionsof other N,N'-disubstituted guanidines of this invention, e.g., those ofTable I, can be produced. If only one of the N- and N'-groups employedas starting material bears a functional group convertible to an [³H]bearing group, the resulting N,N'-disubstituted guanidine will besingly tagged. If both bear such a functional group, the resultingN,N'-disubstituted guanidine will be polytagged.

EXAMPLE 3N-(2-Methyl-4-isothiocyanatophenyl-N'-[2-methylphenyl)guanidine[Di-tolyl-Guanidine-Isothiocyanate (DIGIT)]

a. N-(2-Methyl-4-nitrophenyl)-N'-(2-methyl-phenyl)guanidineHydrochloride and the corresponding free base

A vigorously stirred mixture of 2-methylphenyl-cyanamide [1.107 g, 0.380mmol, prepared from o-toluidine by the method of Safter et al.(1948)]and 2-methyl-4-nitroaniline hydrochloride in chlorobenzene (45ml) was heated at 90° for 3 h and then allowed to cool to 25°. Theresulting pale yellow precipitate was collected, washed with CH₂ Cl₂,and dried, giving 2.284 g (91%) of the hydrochloride of the desiredproduct (pure by NMR). A 681 mg sample was recrystallized twice fromabsolute EtOH to give 600 mg (88%) of the desired product as pale yellowmicrocrystals suitable for the next reaction: mp 196-200; (CD₃ OD, 300MHz) 2.37 (s, 3), 2.47 (s, 3), 7.33-7.40 (m, 4), 7.59 (d, 1), 8.18 (dd,1), 8.27 (d, 1). A 473 mg sample of the hydrochloride was dissolved in50 ml of hot water, filtered, cooled to 25°, and treated with 5 ml of 5NNaOH. The resulting bright yellow precipitate of the title compound(free base) was dried (403 mg, 92%) and then recrystallized twice from95% EtOH to give the analytical sample as yellow platelets: mp 177-179;(DC₃ OD, 300 MHz) 2.31 (s, 6), 7.01-7.35 (m, 5), 7.98 (dd, 1), 8.06 (d,1). Analysis calculated for C₁₅ H₁₆ N₄ O₂ : C, 63.37; H, 5.67; N, 19.71.Found: C, 63.41; H, 5.42; N, 19.90.

b. N-(2-Methyl-4-aminophenyl)-N'-(2-methylphenyl)-guanidinehydrochloride

A Parr hydrogenation flask was charged with a solution ofN-(2-methyl-4-nitrophenyl)-N'-2-(methylphenyl)-guanidine hydrochloride(478 mg) in 30 ml of absolute EtOH. 30% Pd on charcoal (71 mg) was addedand then the mixture was hydrogenated at 60 psi at 25° C. for 12 h. Allfurther operations were carried out under an atmosphere of Ar. Themixture was centrifuged, filtered through Celite and the filtrate wasconcentrated in vacuo to 2 ml. Ether (21 ml) was added and after 4 h at20°, the white precipitate was collected and dried, giving 406 mg (78%)of the title compound (amine hydrochloride) suitable for the nextreaction: mp 232.5°-234.5°, (CD₃ OD, 300 MHz) δ2.22 (s, 3), 2.34 (s, 3),6.60 (dd, 1), 6.66 (d, 1), 6.98 (d, 1), 7.26-7.38 (m, 4).

c. N-(2-Methyl-4-isothiocyanatophenyl)-N'-(2-methylphenyl)guanidineHydrochloride (DIGIT)

NaOAc (1.767 g, 21.5 mmol) and HOAc (0.839 g, 14.0 mmol) were dissolvedin dry MeOH such that the final volume of the solution was 100 ml. A12.7 ml aliquot of this solution was added to 199 mg (0.686 mmol) ofN-(2-methyl-4-aminophenyl)-N'-(2-methylphenyl)-guanidine hydrochlorideunder an Ar atmosphere. Thiophosgene (54.7 ul, 86.7 mg, 0.754 mmol,freshly distilled) was then injected into the stirred reaction mixture.The reaction was complete upon mixing as judged by silica gel TLC(500:100:1, CHCl₃ -MeOH-HOAc). Water (20 ml) was added and the mixturewas concentrated in vacuo to 19 ml.

The next steps were done in rapid succession in order to minimize thepossible reaction of the isothiocyanate group with the guanidine freebase grouping of another molecule. The above 19 ml concentrate wascooled to 0° and treated with ice-cold saturated NaHCO₃ (15 ml). Theresulting mixture containing a white precipitate was extracted withCHCl₃ (4×15 ml). The combined extracts were washed with ice cold brine,dried (MgSO₄), filtered through Celite, and cooled to 0°. Next, excessHCl gas was bubbled through the colorless solution and then the solutionwas concentrated in vacuo to 25 ml and hexane (20 ml) was added. Fouradditional times the mixture was concentrated again and more hexane wasadded. Evaporation of the final mixture to dryness gave crudehydrochloride as a gummy white solid (263 mg, 115%). This was taken upin absolute ethanol (2 ml), and diluted with ether (80 ml) to give acloudy white suspension from which small clusters of white needlesformed on standing. The crystals were centrifuged, washed with ether(3×5 ml), and dried, giving 173 mg (76%) of the title compound: m.p.195°-197° C. (preheated bath); (CD₃ OD), 300 MHz) δ2.347 (s, 3), 2.351(s, 3), 7.23 (d, 1), 7.31 (s, 1), 7.34 (d, 1), 7.26-7.40 (m, 4); IR(KBr) 3466, 3138, 2927, 2152, 2119, 1646, 1631 cm⁻¹. Analysis calculatedfor C₁₆ H₁₇ ClN₄ S: C, 57.74; H, 5.15; N, 16.83. Found: C, 57.60; H,5.20; N, 16.64.

A tri-tritiated version of DIGIT is prepared starting with tritiatedN-(2-methyl-4-aminophenyl)-N'-(2-methylphenyl)-guanidine, which wasprepared by catalytic tritiation (Amersham) ofN-(2-methyl-4-nitro-6-bromophenyl)-N'-(2-methyl-4,6-dibromophenyl)-guanidine.The tri-tritiated amino compound was also used as the immediateprecursor for the preparation of the tritritiated version of the 4-azidocompound the preparation of which is described hereinafter and which wasused in the solubilization of sigma receptors.

EXAMPLE 4 N-Adamantan-1-yl-N'-cyclohexylguanidine-HCl

Adamantan-1-ylcyanamide (514 mg, 2.92 mmol), and cyclohexylaminehydrochloride (398 mg, 2.93 mmol) were finely ground together, andheated at 200° C. for 10 min. The resultant glassy solid was pulverized,and extracted twice with 50 ml boiling 5% HCl. The insoluble materialwas filtered, and dried. 346 mg, mp 264-270 (p.h.b. 240° C.). On coolingthe combined aqueous extracts to 25°, a white ppt. formed, and wasfiltered off, 56 mg. Combined crude yield: 44%. Crystallization of a 50mg sample of the crude product from EtOH/Et₂ O afforded white needles(25 mg, mp 269°-271° C. (p.h.b. 240°), lit. 268°-269° C.). ¹ H (CD₃ OD)1.208-1.474 (m, 5H), 1.744 (s, 9H), 1.967 (s, 8H), 2.119 (5, 3H), 3.434(m, 1H), ¹³ C (CD₃ OD) (broad band decoupled) 25.55, 26.26, 30.96,33.74, 36.74, 42.73.

EXAMPLE 5 N-Cyclohexyl-N'-(2-methylphenyl)guanidine

A suspension of cyclohexylamine hydrochloride (310 mg, 2.28 mmol) and(2-methylphenyl)cyanamide (365 mg, 2.76 mmol) in dry chlorobenzene washeated at 125°-135° for 4 hrs. The solvent was evaporated in vacuo withheating, and the residue partitioned between CH₂ Cl₂ and 20×8 ml 10%HCl. The aqueous extracts were made alkaline to pH 9-9.5, and the whiteprecipitate collected after standing at 4° C. overnight. Tworecrystallizations from EtOH/H₂ O gave 140 mg (22%) of white needles, mp145°-146°, 1H (CD₃ OD) 1.149-2.054 (m, 10 H), 2.164 (s, 3 H), 3.50 (m, 1H), 6.875 (d, 1H, J=7.5 Hz), 6.968 (t, 1H, J=7.5 Hz), 7.118 (t, 1H,J=7.5 Hz), 7.177 (d, 1H, J=7.5 Hz). Anal. Calcd for C₁₄ H₂₁ N₃ : C,72.69; H, 9.15; N, 18.16. Found: C, 72.72; H, 9.24; N, 18.18.

EXAMPLE 6 N-(Adamantan-1-yl)-N'-(2-methylphenyl)guanidine

A suspension of adamantan-1-ylcyanamide (151 mg, 0.857 mmol) ando-toluidine hydrochloride (186 mg, 0.857 mmol) in dry chlorobenzene washeated between 100°-130° C. for 4.5 hrs. The chlorobenzene wasevaporated in vacuo with heating and the residue (285 mg) taken up in 18ml of water. A gummy, insoluble material was discarded. On adjusting theaqueous extract to pH 9-9.5, a precipitate formed (194 mg, 71%). Tworecrystallizations from EtOH/H₂ O gave the analytical sample; mp160°-161°, ¹ H (CD₃ OD) 1.742 (s, 6 H), 2.050 (d, 6H, J=2.4 Hz), 2.029(s, 3 H), 6.956 (j, 1 H, J=8.1 Hz), 7.056 (t, 1H, J=8.1 Hz), 7.168 (t,1H, J=7.5 Hz), 7.213 (d, 1H, J=7.5 Hz). Anal. Calcd for C₁₈ H₂₅ N₃ : C,76.28; H, 8.89; N, 14.83. Found: C, 76.25; H, 8.86; N, 14.60.

EXAMPLE 7 N-(Adamantan-1-yl)-N'-(2-iodophenyl)guanidine HCl

Adamantan-1-ylcyanamide (299 mg, 1.70 mmol) and o-iodoanilinehydrochloride (433 mg 1.70 mmol) were finely ground together and heatedat 200° for 10 min. The resultant black glassy solid was pulverized, andrecrystallized 5 times from EtOH/Et₂ O. The resultant faintly blueneedles (80 mg) were dissolved in 4 ml EtOH, and passed through a short(<1 cm) column packed from bottom to top with Celite, charcoal,activated alumina, and sand. The colorless eluate was then diluted with5 ml Et₂ O, and allowed to stand in an Et₂ O diffusion chamberovernight. The white needles were collected by suction filtration, 40mg, mp 274°-275° C. Addition of another 5 ml Et₂ O yielded a second crop(31 mg) of identical material. Combined yield: 21%. ¹ H (CD₃ OD) 1.779(s, 6H), 2.090 (s, 6H), 2.164 (s, 3 H), 7.168 (t, 1H, J=8.1 Hz), 7.388(d, 1 H, J=9.1 Hz), 7.503 (t, 1 H, J=7.8 Hz), 8.004 (d, 1 H, J=7.8 Hz).

EXAMPLE 8 N-(2-Methyl-4-azido-phenyl)-N'-(2-methylphenyl)guanidine

N-(2-Methylphenyl)-N'-(2-methyl-4-aminophenyl)guanidine dihydrochloride(112 mg, 0.341 mmol) were dissolved in 2 ml H₂ O and 100 ul conc. HCl(1.2 mmol). The solution was cooled in an ice bath, and a solution ofNaNO₂ (42 mg, 0.61 mmol) in 450 ul H₂ O were added. The reaction mixtureturned yellow, and was stirred for 45 min before solid NaN₃ (43 mg,0.661 mmol) was added in a single portion. After N₂ evolution wascaused, a foamy solid (11 mg) was removed and discarded. Solid NaOH (96mg, 2.41 mmol) was added, and the bright yellow precipitate wasextracted with Et₂ O (3x5 ml). Evaporation of the combined Et₂ O layersgave a yellow solid which was crystallized from EtOH/H₂ O: NMR (CD₃ OD)2.279 (s, 3 H), 2.284 (s, 3 H), 6.864 (dd, 1H, J=2.4 Hz, 8.4 Hz), 6.914(d, 1 H, J=2.1 Hz), 7.055 (td, 1 H, J=1.8 Hz, 7.2 Hz), 7.136-7.229 (m,4H).

EXAMPLE 9N-(2-Methyl-4-nitro-6-bromophenyl)-N'-(2-methyl-4,6-dibromophenyl)guanidine

N-(2-Methyl-4-nitrophenyl)-N'-(2-methylphenyl)guanidine, as the freebase (281 mg, 0.987 mmol) was dissolved in 4 ml MeOH, and cooled in anice-bath. N-bromosuccinimide (freshly recrystallized from H₂ O) (531 mg,2.98 mmol) was added in two portions over 15 min. After 1.5 hrs thebrown sludgy reaction mixture was diluted with 4 ml MeOH, and allowed towarm to 25° C. A brown solid was filtered off (266 mg), and crystallizedfrom acetone/H₂ O, to afford brown needles (2.6 mg, 42%, mp 193°-195°C.). Sublimation of a 56 mg sample of these crystals at 0.01 mm Hg and170° afforded the analytical sample as a bright yellow amorphous solid(38 mg, mp 210°-213° C.). NMR (CD₃ OD) 2.357 (s, 3 H), 2.488 (s, 3 H),7.444 (d, 1H, J=1.5 Hz), 7.669 (d, 1H, J=1.8 Hz), 8.033 (d, 1H, 2.1 Hz),8.267 (d, 1H, 2.4 Hz). Anal. Calcd for C₁₅ N₁₃ Br₃ N₄ O₂ : C, 34.58; N,2.52; N, 10.75. Found: C, 34.64; N, 2.47; N, 10.65.

EXAMPLE 10 N,N'-Bis(2-iodophenyl)guanidine

A solution of cyanogen bromide (4.4042 g, 38.2 mmol) and 2-iodoaniline(4.138 g, 18.9 mmol) in H₂ O (70 ml) was heated at 70°-80° C. for 5 h.The reaction mixture was decanted from an off-white solid (1.90 g) whichwas discarded, and the supernatant was heated at the same temperature anadditional 16 h. On cooling to 25° C., the title compound precipitatedfrom solution as its hydrobromide salt and was centrifuged off, anddried (500 mg, 10%). This white powder was dissolved in boiling H₂ O (20ml), and 5N NaOH (2 ml) was added to the clear solution. The resultingwhite precipitate (290 mg) was washed with H₂ O (3×4 ml), andcrystallized from 95% EtOH, to give the title compound (119 mg, 39% fromthe hydrobromide salt) as long white needles: mp 161°-162° C. Onefurther crystallization provided the analytical sample: mp 161°-162° C.Anal. Calcd for C₁₃ N₁₁ N₃ I₂ : C, 33.72; N, 2.39; N, 9.07. Found: C,33.80; N, 2.26; N, 8.78. ¹ N NMR: δ6.790 (t, J=7.8 Hz, 2 H), 7.304 (t,3=7.8 Hz, 2 H), 7.506 (d, 3=7.8 Hz, 2 H), 7.817 (d, 3=7.8 Hz, 2H). IR:729, 753, 1467, 1502, 1572, 1613, 1647, 3056, 3387.

EXAMPLE 11 N,N'-Bis(3-methylphenyl)guanidine

Cyanogen bromide (788 mg, 7.44 mmol) was placed in a 25 ml round bottomflask, and m-toluidine (1.89 g, 17.6 mmol) was added dropwise. After theexothermic reaction had subsided, the residue was taken up in CH₂ Cl₂(20 ml), and was extracted with 5% HCl (5×10 ml). The aqueous extractswere adjusted to pH 10 with 6N NaOH. The resulting precipitate (674 mg,38%) was filtered off and crystallized from EtOH/H₂ O to give the titlecompound (240 mg, 14%) as white needles: mp 105°-106° C. ¹ H NMR: δ2.289(s, 6 H), 6.814 (d, 2 H, J=7.5 Hz), 6.939 (d, 2 H, J=7.5 Hz), 6.981 (s,2 H), 7.141 (t, 2 H, J=7.5 Hz). Anal. Calcd for C₁₅ H₁₇ N₃ : C, 75.28;H, 7.16; N, 17.56. Found: C, 75.42; H, 7.11; N, 17.43.

REFERENCES

¹ Geluk, H. W., et al., J. Med. Chem. 12:712 (1969).

² Kazarinova, N. F., et al., Zn. Anal., Khim. 28:1853 (1973); Chem.Abstr. 80:97021 (1973).

EXAMPLE 12 Synthesis of N,N'-Di(o-tolyl)-2-imino-imidazolidine

a. Synthesis of N,N' Ditolyl oxalodiamide

Oxalyl chloride (32 mmol) in methylene chloride (16 mL) was addeddropwise to a solution of o-toluidine (67 mmol) in methylene chloride (4mL) over a period of 10 min at 4° C. After the exotherm subsided, thesolution was removed from the ice bath and stirred at ambienttemperature for 2 h. A white precipitate had formed. The precipitate wasfiltered off, dried, and found to weigh 724.6 mg (90%). The amide andthe hydrooxalate salts were partially dissolved in methylene chloride(20 mL) and extracted with 1N HCl (5×, 15 mL). The resultant whitesuspension was filtered to provide a white solid (61%, mp 103°-104° C.).¹ H NMR (CD₃ CN/DMSO): 2.259 (6H, s), 7.128-7605 (8H, m). IR (KBr):1298.7, 1642.9 (amide).

b. Synthesis of N,N' Bistolyl ethylene diamine

The following procedure was adapted from H. C. Brown, J. Org. Chem.38:912 (1978). Diborane (5 mmol) in THF was added dropwise to a THFsolution of N,N' Ditolyl oxalodiamide (443.0 mg, 1.65 mmol) over 10 minat 0° C. After 30 min, the reaction mixture was allowed to stir atambient temperature for 6 h. Then the solution was refluxed for 3 h. Theresulting yellowish solution was allowed to cool to 25° C. The solutionwas then acidified dropwise with 15% HCl (15 mL) via an additionalfunnel over 20 min. Gas evolution was noted and a white precipitate hadformed. The THF was then distilled off from the water throughrotoevaporation at 25° C. The water was then made basic with an excessof NaOH and then extracted with ether. The ether layer was washed withbrine, then dried over anhydrous potassium carbonate. The ether layerwas then concentrated to dryness to provide a tannish brown liquid. Theliquid was immediately taken up again in dry ether. Following thisprocedure, the solution was made acidic by adding ethereal HCl (10 mL)dropwise. A white solid had formed. This solid was immediately filteredoff and dissolved in ethanol (5 mL) and placed into an ether diffusionchamber. After 2 days, white prisms were found (158.1 mg, 30.6%),mp=268°-270° C.

IR (KBr): in comparison with IR of diamide the bands at 1643.8 and1298.7 had disappeared.

c. Synthesis of N,N' Bistolyl-2-imino-imidazolidine

N,N' Bistolyl ethylene diamine (105.8 mg, 0.44 mmol) was taken up inEtOH (3 mL) to provide a light purple solution. This solution was thenplaced in a one-necked round-bottom flask (25 mL) equipped with magneticstirbar and reflux condenser. To this solution, cyanogen bromide (50 mg,0.47 mmol) in ethanol (2 mL) was added in a single portion. Theresultant reaction mixture was stirred for 1 h. It was noted that thesolution turned clear. The solution was then brought to reflux andmaintained at that temperature for 16 h. The reflux condenser was thenremoved, allowing the solvent to evaporate. The reaction mixture wasthen fused at 150° C. for 30 min to provide a brown solid. This solidwas immediately taken up in ethanol (4 mL) and placed into a centrifugetube. To this solution 1N NaOH was added (8 mL) to provide a "whispy"tan precipitate. After several failed attempts to pellet theprecipitate, the solution was simply extracted with chloroform (20 mL).The chloroform was concentrated to dryness to provide a clear oil (108.1mg, 92.6%).

EXAMPLE 13 Characteristics of [³ H]DTG binding to guinea pig brainmembranes

Synthesis of [³ H]DTG resulted in a pure homogenous product of highspecific radioactivity (52 Ci/mmol). [³ H]DTG bound specifically,saturably, reversibly, and with high affinity to guinea pig brainmembrane. In a typical experiment with 0.9 nM [³ H]DTG (30,000 cpm, 50%counting efficiency) the total binding was 2700 cpm while thenonspecific binding in the presence of 10 uM DTG or 10 uM haloperidolwas 50-150 cpm. Routinely, a specific binding to 90-97% of total bindingwas observed. At room temperature the binding of [³ H]DTG reachedequilibrium after 60-90 minutes and it was fully reversible afteraddition of 10 uM unlabeled DTG. Specific binding was linear with tissueconcentration between 2-40 mg tissue (original wet brain weight perassay tube). Binding of radioactivity to the glass fiber filters in theabsence of membranes was 10-20 cpm. Boiling of membranes at 100° C. for10 minutes prior to assay almost completely (90%) abolished specific [³H]DTG binding as did treatment of the membranes with trypsin and pronase(0.01 mg/ml for 30 min at room temperature), indicating that proteincomponents are important for the receptors binding ability.

To determine the equilibrium saturation binding of [³ H]DTG to guineapig brain membranes, membranes prepared as described herein wereincubated with [³ H]DTG at various concentrations from 0.3 nM to 90 nMin 1 ml 50 nM Tris/HCl buffer, pH 7.4, for 120 minutes at roomtemperature. Values obtained were the mean of quadruplicatedeterminations.

A Scatchard analysis of the saturation data shows a linear Scatchardplot with an apparent K_(D) of 28 nM and a maximum number of bindingsites (Bmax) of 85 pmol/g brain tissue (original wet weight). Analysisof the binding data with the curve fitting program LIGAND, Munson, P.J., et al., Anal. Biochem. 107:220-239 showed high compatibility with aone site binding model.

EXAMPLE 14 Radioligand Binding Assays

Frozen guinea pig brains (Pel-Freeze, Rogers, AK) were homogenized in 10volumes (w/v) of 0.32M sucrose using a Polytron homogenizer. Thehomogenate was spun at 900×g for 10 minutes at 4° C. The supernatant wascollected, and spun at 22,000×g for 20 minutes at 4° C. The pellet wasresuspended in 10 volumes of 50 mM Tris/HCl buffer, pH 7.4, incubated at37° C. for 30 minutes and spun again at 22,000×g for 20 minutes at 4° C.The pellet was then resuspended in 10 volumes of 50 mM Tris/HCl buffer,pH 7.4 and 10 ml aliquots of this membrane suspension were stored frozenat -70° C. until used in the binding assay. No effects of prolongedstorage (>3 months) of the membranes at -70° C. on sigma receptor numberor affinity for [³ H]DTG binding were observed.

For radioreceptor assays aliquots of the frozen membrane suspension werethawed and diluted tenfold with 50 nM Tris/HCl buffer, pH 7.4. To 12×75mm polystyrene or glass test tubes were added 0.8 ml of membranesuspension, 0.1 ml [³ H]DTG or (+)[³ H]3-PPP for a final concentrationof 0.9 nM, and 0.1 ml of unlabeled drugs or buffer. The proteinconcentration in the 1 ml final incubation volume was 800 ug,corresponding to 32 mg of brain tissue (original wet weight).Nonspecific binding was defined as that remaining in the presence ofeither 10 uM DTG or haloperidol for both the [³ H]DTG and the (+)[³H]3-PPP binding. After incubation for 90 minutes at room temperature themembrane suspension was rapidly filtered under vacuum through WhatmanGF/B glass fiber filters using a Brandel 48 well cell harvester(Brandel, Gaithersburg, Md.). The filters were washed with 3×5 mlice-cold 50 nM Tris buffer (pH 7.4 at room temperature). The filterswere dissolved in 10 ml each of Cytoscint (Westchem Products, San Diego,Calif.) and radioactivity was measured by liquid scintillationspectrometry at a counting efficiency of 35-50%. Saturation data wereevaluated by Scatchard analysis using both the EBDA NcPherson, G. A.,Computer Programs Biomed. 17:107-114 (1983), and LIGAND Munson, P. J.,et al., Anal. Biochem. 107:220-239 (1980), data analysis programs on anIBM Personal Computer-AT. IC₅₀ values were determined by plottingdisplacement curves onto semilogarithmic graph paper followed byinterpolation or by computerized non-linear least squares curve fitting(Fischer, J. B. et al., J. Biol. Chem. 263:2808-2816 (1988).

Utilizing the radioligand binding assay described above, the sigmareceptor binding activity based on [³ H]DTG displacement activity (IC₅₀value) for the fourteen (14) N,N'-disubstituted guanidine compoundslisted in Table I below was determined. The IC₅₀ value for each compoundis reported in Table I.

                  TABLE I                                                         ______________________________________                                                                 IC.sub.50 vs                                         Compound                 [.sup.3 H]DTG (nM)                                   ______________________________________                                        N,N'-di-o-tolyl-guanidine                                                                              32 ± 1                                            N,N'-di-n-butyl-guanidine                                                                              750 ± 33                                          N,N'-diphenyl-guanidine  397 ± 21                                          N,N'-diadamantyl-guanidine                                                                             17 ± 1                                            N-adamantyl-N'-2-methylphenyl-guanidine                                                                 8 ± 1                                            N,N'-di-(2-methyl-4-bromophenyl)guanidine                                                              37 ± 3                                            N-(2-iodophenyl)-N'-(2-methylphenyl)-                                                                  21 ± 1                                            guanidine                                                                     N-(2-methyl-4-nitrophenyl)-N'-(2-methyl-                                                               37 ± 5                                            phenyl)-guanidine                                                             N,N'-di-(2,6-dimethylphenyl)guanidine                                                                   90 ± 18                                          N-(2,6-dimethylphenyl)-N'-(2-methylphenyl)-                                                            70 ± 3                                            guanidine                                                                     N-(adamantyl)-N'-(cyclohexyl)guanidine                                                                 13 ± 2                                            N,N'-di(cyclohexyl)guanidine                                                                           71 ± 7                                            N-(2-iodophenyl)-N'-(adamantyl)guanidine                                                                6 ± 5                                            N-(2-methylphenyl)-N'-(cyclohexyl)guanidine                                                            13 ± 1                                            N-(2-methyl-4-azidophenyl)-N'-(2-methyl-                                                               20 ± 1                                            phenyl)-guanidine                                                             ______________________________________                                    

EXAMPLE 15 Drug Specificity of [³ H]DTG Binding

Displacement experiments were performed with drugs that are consideredtypical sigma ligands, as well as with drugs considered to beprototypical ligands for other neurotransmitter, neuromodulator, anddrug receptors. The IC₅₀ vs [³ H]DTG and vs. [³ H]3-PPP results aregiven in Table II below. These experiments showed that the [³ H]DTGbinding site is stereoselective for dextrorotatory benzomorphan opiatesand for (-)butaclamol; does not significantly interact with drugs thathave high affinities for acetylcholine, benzodiazepine, GABA, nor withmu, delta, or kappa opioid receptors; has a high affinity forhaloperidol and several drugs belonging to the phenothiazine class ofantipsychotics (haloperidol had the highest displacement potency of alldrugs tested); and has a moderate affinity for several other classes ofpsychoactive drugs, which included several tricyclic antidepressants,PCP, and the kappa opioid receptor ligand U50, 488H.

                  TABLE II                                                        ______________________________________                                                     IC.sub.50 vs.                                                                             IC.sub.50 vs.                                                     [.sup.3 H]DTG (nM)                                                                        (+)[.sup.3 H]3-PPP (nM)                              Drug         (±SEM)   (±SEM)                                            ______________________________________                                        Haloperidol    5 ± 0.3                                                                              17 ± 1                                            DTG          28 ± 1   53 ± 9                                            Perphenazine  42 ± 10 21 ± 3                                            (+)Pentazocine                                                                             43 ± 2    8 ± 3                                            (-)Pentazocine                                                                             135 ± 3  81 ± 1                                            (±)Pentazocine                                                                          69 ± 1   ND                                                   (+)3-PPP     76 ± 4    33 ± 12                                          (-)3-PPP     280 ± 21 235 ± 60                                          (+)Cyclazocine                                                                             365 ± 25  47 ± 12                                          (-)Cyclazocine                                                                             2,600 ± 210                                                                            1,000 ± 0                                         Spiperone    690 ± 21 ND                                                   (-)Butaclamol                                                                              530 ± 49 183 ± 5                                           (+)Butaclamol                                                                              2,150 ± 250                                                                            2,100 ± 71                                        (+)SKF 10,047                                                                              625 ± 88 93 ± 5                                            (-)SKF 10,047                                                                              4,000 ± 566                                                                            2,850 ± 390                                       PCP          1,050 ±  106                                                                           1,000 ± 71                                        U50,488H     1,350 ± 106                                                                            ND                                                   Trifluoperazine                                                                            345 ± 4  ND                                                   Trifluopromazine                                                                           605 ± 67 ND                                                   Chlorpromazine                                                                             1,475 ± 265                                                                            ND                                                   Amitriptyline                                                                              300 ± 7  ND                                                   Imipramine   520 ± 14 ND                                                   Desipramine  4,000 ± 566                                                                            ND                                                   Nortriptyline                                                                              2,000 ± 640                                                                            ND                                                   Guanabenz    4,600 ± 283                                                                            ND                                                   Clonidine    >10,000     ND                                                   Cocaine      >10,000     ND                                                   ______________________________________                                         *IC.sub.50 is the molar concentration of the drug needed to produce           halfmaximal displacement of [.sup.3 H]DTG from sigma receptors. This is a     direct measure of the sigma receptor binding potency of the drug.             ND = not determined.                                                     

The above IC₅₀ s represent the average from 2-4 separate experiments (intriplicate). The following compounds caused no significant displacementat a 10 uM concentration: scopolamine, 5-OH-tryptamine, diazepam,bicuculline, picrotoxin, hexamethonium, dopamine, apomorphine, GABA,gamma-guanidino butyric acid, morphine, DAGO, metorphamide, dynorphin A,[leu⁵ ] enkephalin, beta-endorphin, naloxone, guanidino acetic acid,creatine, creatinine, 1,1-dimethyl-4-guanidine, methyl-guanidine,beta-guanidino propionic acid and cimetidine.

EXAMPLE 16 Drug specificity of [³ H]DTG binding compared to (+)-[³H]3-PPP binding

Comparing the drug specificity of [³ H]-DTG binding with that of (+)[³H]3-PPP in the guinea pig, it was found that (+)[³ H]3-PPP boundspecifically, saturably (linear Scatchard plot), reversibly and withhigh affinity to guinea pig brain membranes (K_(D) =30 nm, Bmax=80pmol/g fresh brain weight). The drug specificity profile of the (+)[³H]3-PPP binding in the guinea pig (Table II) was found to be verysimilar to that reported in the rat. Largent et al. (1984), supra.Moreover, the drug specificity profiles of typical sigma receptor activedrugs in the (+)[³ H]3 PPP and [³ H]-DTG binding assays were highlycorrelated (r=0.95; p≦0.00001) which is consistent with the twocompounds labeling the same sites.

EXAMPLE 17 Autoradiography Studies

Male Sprague Dawley rats (200-250 g) and NIH guinea pigs (300-350 g)were sacrificed, their brains rapidly removed and processed for receptorautoradiography according to the method of Herkenham et al., J.Neuroscience 2:1129-1149 (1982).

Fifteen um thick slide-mounted brain sections were incubated for 45minutes in 50 nM Tris-HCl (pH 8.0, 22° C.) containing 1 mg/ml bovineserum albumin (BSA) and 2 nM [³ H]DTG. Adjacent sections were incubatedwith 10 uM haloperidol or 10 uM DTG to measure nonspecific binding.Incubations were terminated by 4×2 minute washes in 10 nM Tris-HCl (pH7.4, 4° C.) with 1 mg/ml BSA, rapidly dried under a stream of cool airand placed in x-ray cassettes with ³ H-sensitive film ³ H-ultrofilm,LKB). Films were developed 6-8 weeks later (D-19, Kodak).

EXAMPLE 18 Autoradiographic visualization of [³ H]DTG binding

Receptor autoradiography studies on guinea pig and rat brain sectionsusing [³ H]DTG showed a low density of specific binding diffuselydistributed throughout the gray matter of the rat and guinea pig brain.Superimposed on this homogeneous binding patterns was a heterogeneousdistribution of enriched binding in limbic and sensorimotor structures.The pattern of binding was more distinct in the guinea pig than rat.Similar observations for (+)[³ H]3-PPP autoradiography have beenreported. Largent et al. (1986), supra. Thus, description of [³ H]DTGbinding was drawn primarily from the guinea pig. In the forebrain,limbic structures moderately to densely labeled by [³ H]DTG were thediagonal band of Broca, septum, hypothalamus (especially theparaventricular nucleus), anterodorsal thalamic nucleus and zonaincerta. Sensorimotor thalamic nuclei moderately to densely labeledincluded the thalamic taste relay and reticular nuclei. Other thalamicnuclei labeled were the paraventricular and habenular nuclei. Very densebinding was seen in the choroid plexus. In the cortex dense [³ H]DTGlabeling occupied layer III/IV of retrospenial piriform, and entorhinalcortices. The rest of the cortex contained a low level of homogeneousbinding. The hippocampal formation exhibited discrete binding in thepyramidal granular cell layers. Sensorimotor areas of the midbrain wereselectively labeled by [³ H]DTG. The oculomotor nucleus, and morecaudally, the trochlear nucleus were very densely labeled, and thesuperior colliculus and red nucleus had moderate levels of binding.Other midbrain nuclei labeled were the dorsal raphe, interpeduncularnucleus, central gray, and the substantia nigra, para compacta. Theselective labeling of the para compacta in the guinea pig contrastedwith the low to moderate density of labeling present throughout thesubstantia nigra of the rat. In addition, very dense binding was foundin the subcommissural organ. In the hindbrain the locus coeruleus wasthe most densely labeled nucleus. Sensorimotor nuclei enriched in [³H]DTG binding sites were the trigeminal motor nucleus, nucleus of thefacial nerve, nucleus of the solitary tract, dorsal motor nucleus of thevagus, and the hypoglossal nucleus. Moderate to dense binding was alsofound throughout the gray matter of the cerebellum, and in the pontinereticular nuclei.

EXAMPLE 19 Drug Specificity of [³ H]AZ-DTG binding

The haloperidol-sensitive sigma receptor binds [³H](+)3-[3-hydroxyphenyl]-N-(1-propyl)piperidine([³ H](+)-3-PPP) and [³H]1,3-di-o-tolylguanidine ([³ H]DTG), with high affinity. In order toelucidate its structure, photoaffinity labeling of the sigma receptorfrom guinea pig brain was accomplished using a novel radioactivephotolabile derivative of DTG, [³ H]-m-azido-1,3-di-o-tolylguanidine ([³H]AZ-DTG). In the dark, [³ H]AZ-DTG binds reversibly to sigma sites inbrain membranes with high affinity (kd=28 nM). The drug specificityprofile of [³ H]AZ-DTG binding to brain membranes is identical to thatof the prototypical sigma ligands [³ H]DTG and [³ H](+)-3-PPP. Forphotoaffinity labeling, membrane suspensions containing proteaseinhibitors were preincubated in the dark with [³ H]AZ-DTG, then filteredand washed over Whatman GF/B glass fiber filters. The filters were thenirradiated with long-wavelength UV light for a 15 minute period.Filter-bound proteins were solubilized with 50 mM Tris pH 7.4, 0.1%sodium dodecyl sulfate. Solubilized proteins were subjected toSDS-polyacrylamide gel electrophoresis. Fluorography of the SDS-PAGEgels revealed that [³ H]AZ-DTG was selectively incorporated into a 29 kDpolypeptide. Labeling of this polypeptide was completely blocked by thesigma ligands DTG, (+)-3-PPP, (+)pentazocine, and haloperidol at aconcentration of 10 uM, while labeling was unaffected by morphine,serotonin, dopamine, scopolamine, or GABA at the same concentration.These results represent the first estimate of the size of the bindingsubunit of the haloperidol-sensitive sigma receptor.

EXAMPLE 20 Additional sigma receptor binding assays

Sigma receptor binding assays using guinea pig brain membranehomogenates and the radioligands [³ H]DTG and (+)[³ H]3-PPP were done aspreviously described (Weber et al., P.N.A.S. (USA) 83:8784-8788 (1986)).Briefly, frozen whole guinea-pig brains (Biotrol, Indianapolis, Ind.)were homogenized in 10 volumes (w/v) of ice-cold 320 mM sucrose using aBrinkman polytron. The homogenate was centrifuged at 1,000×g for 20minutes at 4° C. The supernatant was centrifuged at 20,000×g for 20minutes at 4° C. The resulting pellet was resuspended in 10 initialvolumes of 50 mM Tris/HCl buffer at pH 7.4 and centrifuged at 20,000×gfor 20 minutes at 4° C. The resulting pellet was resuspended in 5initial volumes ice-cold 50 mM Tris/Hcl (pH 0.4), and the final volumewas adjusted to yield a protein concentration of 3 mg/ml, as determinedby dye-binding protein assay (Biorad) using BSA as the standard.Aliquots of 20-ml were stored at -70° C. until used, with no detectableloss of binding.

For [³ H]DTG binding assays, 20-ml aliquots of the frozen membranesuspension were thawed and diluted 1:3 in 50 mM Tris/HCl (pH 7.4). To12×75 mm polystyrene test tubes were added 0.8 ml of diluted membranesuspension, 0.1 ml of [³ H]DTG (46 Ci/mmol; see Weber et al., P.N.A.S(USA) 83 :8784-8788 (1986) or (+)[³ H]3-PPP (NEN, 98 Ci/mmol) to yield afinal concentration of 1.4 nM, and 0.1 ml of unlabelled drugs or buffer.The protein concentration in the 1-ml final incubation volume was 800ug/ml, corresponding to 32 mg of brain tissue (original wet weight) andto a tissue concentration within the linear range for specific binding.Non-specific binding was defined as that remaining in the presence of 10uM haloperidol. Specific binding constituted >90% of total [³ H]DTGbinding. Incubations were terminated after 90 minutes at roomtemperature by addition of 4 ml of ice-cold 50 mM Tris/HCl (pH 7.4) andrapid filtration of the membrane suspension through Whatman GF/Bglass-fiber filters under vacuum, using a 48-well cell harvester(Brandel, Gaithersburg, Md.). The filters were washed 2 times with 4 mlof 50 mM Tris/HCl (pH 7.4). Total filtration and washing time was lessthan 20 seconds. Each filter was dissolved in 10 ml Cytoscint (Westchem,San Diego, Calif.), and radioactivity was measured by liquidscintillation spectrometry at a counting efficiency of approximately50%. IC₅₀ values were determined by interpolation fromdisplacement-curve plots on semilogarithmic graph paper.

The IC₅₀ binding values (nM) are as follows: N,N-di(o-tolyl)guanidine(DTG, 32); N-(2-iodophenyl)-N'-(adamant-1-yl)guanidine (AdIpG, 6.2±0.7);N-(o-tolyl)-N'-(adamant-1-yl)guanidine (AdTG, 7.6±0.3);N,N'-di(adamant-1-yl)guanidine (DAG, 11.8±3.4);N-(cyclohexyl)-N'-(adamant-1-yl)guanidine (AdChG, 12.5±2.2);N-(o-tolyl)-N'-(cyclohexyl)guanidine (13.0±1.0);N,N'-di-(2,6-dimethylphenyl)guanidine (DXG, 90±18);N-(o-tolyl)-N'-(4-amino-2-methylphenyl)guanidine (NH₂ -DTG, 280±20);N,N'-di(phenyl)guanidine (DPG, 397±21);N-(o-tolyl)-N'-(o-iodophenyl)guanidine (IC₅₀ =21);N,N'-di-(p-bromo-o-methylphenyl)guanidine (IC₅₀ =37);N,N'-di-(m-n-propylphenyl)guanidine (IC₅₀ =36);N-(o-tolyl)-N'-(p-nitro-o-tolyl)guanidine (IC₅₀ =37);N,N'-di-(1-tetralinyl)guanidine (IC₅₀ =58);N-(o-tolyl)-N'-(o-xylyl)guanidine (IC₅₀ =70); N,N'-di-(o-xylyl)guanidine(IC₅₀ =90); N,N'-di-(cyclohexyl)guanidine (IC₅₀ =71);N-(3,5-di-methyl-1-adamantanyl)-N'-(o-tolyl)guanidine (IC₅₀ =15);N-(3,5-di-methyl-1-adamantanyl)-N'-(o-iodophenyl)guanidine (IC₅₀ =16);N-(1-adamantyl)-N'-(o-nitrophenyl)guanidine (IC₅₀ =30);N,N'-di-(endo-2norbornyl)guanidine (IC₅₀ =16);N-(exo-2-isobornyl)-N'-(o-iodophenyl)guanidine (IC₅₀ =18);N,N'-di-(exo-2-norbornyl)guanidine (IC₅₀ =22);N-(exo-2-isobornyl)-N'-(o-tolyl)guanidine (IC₅₀ =25);N-(o-iodophenyl)-N'-(t-butyl)guanidine (IC₅₀ =20);N,N'-dibenzylguanidine (IC₅₀ =90);N-(adamant-1-yl)-N'-(o-isopropylphenyl)guanidine (IC₅₀ =24);N-(adamant-2-yl)-N'-(p-iodophenyl)guanidine (IC₅₀ =2.7);N-(cyclohexyl)-N'-(p-bromo-o-tolyl)guanidine (IC₅₀ =5.5);N-(adamantan-2-yl)-N'-(o-iodophenyl)guanidine (IC₅₀ =5.2);2-imino-1,3H-dibenzo[d,f]-[1,3]-diazepine (Bridge-DPG, >10,000);N,N'-di(methyl)guanidine (DMG, >10,000); (+)-3-PPP (76±4); (-)-3-PPP(280±21); (+)-pentazocine (43±2); (-)-pentazocine (135±3);(-)-cyclazocine (2600±210); (-)-SKF140047 (4000±566); haloperidol(5±0.3); BMY 14802 (120±15); rimcazole (1400±100); tiospirone (233±52);perphenazine (42±10); chlorpromazine (1475±265); sulpiride (>10,000);TCP (1100±110); PCP (1050±106); and MK-801 (>10,000).

The compound of the invention were found to be potent ligands of sigmareceptors as determined by their ability to displace [³ H]DTG from sigmareceptors in guinea-pig brain homogenates, the most potent beingN-adamantan-1-yl-N'-(p-bromo-o-tolyl)guanidine with an IC₅₀ of 2.7 nM.

As noted above, the compounds of this invention are useful asanti-hypertensive agents and can be used in the same manner as knownantihypertensive agents, e.g., methyldopa, metoprolol tartrate andhydralazine hydrochloride.

Like guanidines generally and N,N'-diphenyl-guanidine specifically, thedisubstituted guanidines of this invention, including those of FormulaeI and II, are accelerators for the vulcanization of rubbers, e.g.,natural rubbers and epoxy group-containing acrylic rubber, and can beused for such purpose in the same manner as N,N'-diphenylguanidine. Thus[³ H]-DTG can be incorporated into a vulcanized rubber object, e.g., atire tread, and rate of loss of rubber therefrom by water can bemonitored by rate of loss of radioactivity.

The preceding examples can be repeated with similar success bysubstituting the generically or specifically described reactants and/oroperating conditions of this invention for those used in the precedingexamples.

From the foregoing description, one skilled in the art can easilyascertain the essential characteristics of this invention, and withoutdeparting from the spirit and scope thereof, can make various changesand modifications of the invention to adapt it to various usages andconditions.

What is claimed is:
 1. A method of treating a human being suffering froma psychotic mental illness associated with hallucinations, whichcomprises administering thereto, in an amount effective to amelioratethe hallucinations, a non-heterocyclic N,N'-disubstituted guanidinewhich is an antagonist to the sigma receptor binding activity of ahallucinogenic benzomorphan.
 2. A method according to claim 1, whereinthe N,N'-di-substituted guanidine is N,N'-dibutylguanidine,N,N'-diphenylguanidine, N,N'-di-o-tolyl-guanidine,N,N'-di-(2-methyl-4-bromophenyl)guanidine,N,N'-di-(2-methyl-4-iodo-phenyl)guanidine,N-(2-methyl-4-azidophenyl)-N'-(2-methylphenyl)guanidine,N,N'-diadamantylguanidine, N-(2-adamantyl)-N'-(2-methylphenyl)guanidine,N-(2-iodophenyl)-N'-(2-methyl-phenyl)guanidine,N-(2-methyl-4-nitrophenyl)-N'-(2-methyl-phenyl)guanidine,N,N'-di-(2,6-dimethylphenyl)-guanidine,N-(2,6-dimethylphenyl)-N'-(2-methylphenyl)guanidine,N-(adamantyl)-N'-(cyclohexyl)guanidine, N,N'-di(cyclohexyl)guanidine,N-(2-iodophenyl)-N'-(adamantyl)guanidine,N-(2-methylphenyl)-N'-cyclohexylguanidine andN-adamantyl-N'-phenylguanidine.
 3. The method of claim 1 wherein thehuman being has schizophrenia.
 4. The method of claim 1 wherein theguanidine is N-(1-adamantyl)-N'-(o-tolyl)guanidine.
 5. The method ofclaim 4 wherein the human being has schizophrenia.
 6. The method ofclaim 1 wherein the guanidine is of the formula: ##STR11## wherein R andR' each is alkyl of at least 4 carbon atoms, a cycloalkyl of 3 to 12carbon atoms or a carbocyclic aryl or at least 6 carbon atoms.
 7. Themethod of claim 6 wherein R is o-tolyl and R' is adamantyl.
 8. Themethod of claim 1 wherein the guanidine is of the formula: ##STR12##wherein X and Y are independently a branched or straight chain C₁ -C₁₂alkylene or a branched or straight chain C₂ -C₁₂ unsaturated alkylene orwherein one of X and Y is a single bond;R and R' are independentlyhydrogen, a cycloalkyl group of at least 3 carbon atoms, a carbocyclicaryl group of at least 6 carbon atoms, aralkyl of at least 6 carbonatoms and containing 1-3 separate or fused rings, and wherein each of Rand R' may be substituted in 1-3 positions.
 9. The method of claim 1wherein the N,N'-disubstituted guanidine is(+)-N-(2-exonorbornyl)-N'-(2-iodophenyl)guanidine;(-)-N-(2-exonorbornyl)-N'-(2-iodophenyl)guanidine;(+)-N-(2-endonorbornyl)-N'-(2-iodophenyl)guanidine;(-)-N-(2-endonorbornyl)-N'-(2-iodophenyl)guanidine;(+)-N-(2-endonorbornyl)-N'-(o-tolyl)guanidine;(-)-N-(2-endonorbornyl)-N'-(o-tolyl)guanidine;(+)-N-(2-exonorbornyl)-N'-(o-tolyl)guanidine;(-)-N-(2-exonorbornyl)-N'-(o-tolyl)guanidine;(+)-N,N'-di-(endo-2-norbornyl)guanidine;(-)-N,N'-di-(endo-2-norbornyl)guanidine;(+)-N-(exo-2-isobornyl)-N'-(o-iodophenyl)guanidine;(-)-N-(exo-2-isobornyl)-N'-(o-iodophenyl)guanidine;(+)-N,N'-di-(exo-2-norbornyl)-guanidine;(-)-N,N'-di-(exo-2-norbornyl)guanidine;(+)-N-(exo-2-isobornyl)-N'-(o-tolyl)guanidine;N,N'-di-(1-tetralinyl)guanidine; or(-)-N-(exo-2-isobornyl)-N'-(o-tolyl)guanidine.
 10. The method of claim 1wherein the guanidine is administered as a water-soluble salt.
 11. Themethod of claim 3 wherein the guanidine is administered as awater-soluble salt.
 12. The method of claim 4 whereinN-(1-adamantyl)-N'-(o-tolyl)guanidine is administered as a water-solublesalt.
 13. A method of treating a human being suffering from a psychoticmental illness associated with hallucinations, which comprisesadministering thereto, in an amount effective to ameliorate thehallucinations, a non-heterocyclic N,N'-disubstituted guanidine whichhas high binding affinity to the sigma receptor and which is anantagonist to the sigma receptor binding activity of a hallucinogenicbenzomorphan.
 14. The method of claim 13, wherein saidN,N'-disubstituted-guanidine has the formula: ##STR13## wherein X and Yare independently a branched or straight chain C₁ -C₁₂ alkylene or abranched or straight chain C₂ -C₁₂ unsaturated alkylene or wherein oneof X and Y is a single bond;R and R' are independently hydrogen, acycloalkyl group of at least 3 carbon atoms, a carbocyclic aryl group ofat least 6 carbon atoms, aralkyl of at least 6 carbon atoms andcontaining 1-3 separate or fused rings, and wherein each of R and R' maybe substituted in 1-3 positions.
 15. The method of claim 14, whereinsaid N,N'-disubstituted guanidine is N,N'-dibenzylguanidine,N,N-di(o-methylbenzyl)guanidine, or N,N'-di(adamantanemethyl)guanidine.16. The method according to claim 13, wherein the human being isschizophrenic.
 17. The method of claim 13 wherein the N,N'-disubstitutedguanidine is N-(o-tolyl)-N'-(o-iodophenyl)guanidine;N,N'-di-(m-n-propylphenyl)guanidine; N,N'-di(p-bromo-o-tolyl)guanidine;N-(o-tolyl)-N'-(p-nitro-o-tolyl)guanidine;N,N'-di-(1-tetralinyl)guanidine; N-(o-tolyl)-N'-(o-xylyl)guanidine;N,N'-di-(o-xylyl)guanidine; N-(2-adamantyl)-N'-(o-iodophenyl)guanidine;N-(1-adamantanyl)-N'-(o-tolyl)guanidine;N-(3,5-dimethyl-1-adamantanyl)-N'-(o-tolyl)guanidine;N-(3,5-dimethyl-1-adamantyl)-N'-(o-iodophenyl)guanidine;N-(1-adamantyl)-N'-(o-nitrophenyl)guanidine;N-(o-iodophenyl)-N'-(t-butyl)guanidine; N,N'-dibenzylguanidine;N-(adamant-1-yl)-N'-(o-isopropylphenyl)guanidine;N-(adamant-1-yl)-N'-(p-bromo-o-tolyl)guanidine;N-(cyclohexyl)-N'-(p-bromo-o-tolyl)guanidine;N-(adamant-2-yl)-N'-(o-iodophenyl)guanidine;N-(adamant-2-yl)-N'-(o-tolyl)guanidine;N,N'-di(o-methylbenzyl)guanidine; N,N'-di(cyclohexyl)guanidine;N-(cyclohexyl)-N'-(p-iodophenyl)guanidine;N-(cyclohexyl)-N'-(adamantan-1-yl)guanidine; orN,N'-di(1-adamantanemethyl)guanidine.
 18. The method of claim 13 whereinthe guanidine is N-(1-adamantyl)-N'-(o-tolyl)guanidine.
 19. The methodof claim 13 wherein the human is schizophrenic.
 20. A method of treatinga human afflicted with a psychotic disease which comprises administeringto the human an anti-psychosis effective amount ofN-(1-admantyl)-N'-(o-tolyl)guanidine.
 21. The method of claim 20 wherethe human has schizophrenia.
 22. The method of claim 20 wherein apharmaceutical composition comprising a pharmaceutically acceptablecarrier and the N-(1-admantyl)-N'-(o-tolyl)guanidine is administered tothe human.
 23. The method of claim 22 wherein the pharmaceuticalcomposition is administered orally to the human.
 24. The method of claim22 wherein the pharmaceutical composition is administered parenterallyto the human.
 25. The method of claim 20 whereinN-(1-adamantyl)-N'-(o-tolyl)guanidine is administered as a water-solublesalt.
 26. The method of claim 21 whereinN-(1-adamantyl)-N'-(o-tolyl)guanidine is administered as a water-solublesalt.
 27. A method of treating the human being afflicted with apsychotic disease which comprises administering to the human being ananti-psychosis effective amount of a non-heterocyclic N,N'-disubstitutedguanidine.
 28. The method of claim 27 wherein the guanidine has theformula: ##STR14## wherein R and R' each is an alkyl group of at leastfour carbon atoms, a cycloalkyl group of 3 to 12 carbon atoms or acarbocyclic aryl group or at least 6 carbon atoms.
 29. The method ofclaim 27 wherein the guanidine is of the formula: ##STR15## wherein Xand Y are independently a branched or straight chain C₁ -C₁₂ alkylene ora branched or straight chain C₂ -C₁₂ unsaturated alkylene or wherein oneof X and Y is a single bond;R and R' are independently hydrogen, acycloalkyl group of at least 3 carbon atoms, a carbocyclic aryl group ofat least 6 carbon atoms, aralkyl of at least 6 carbon atoms andcontaining 1-3 separate or fused rings, and wherein each of R and R' maybe substituted in 1-3 positions.
 30. The method of claim 27 wherein theguanidine is N-(o-tolyl)-N'-(o-iodophenyl)guanidine;N,N'-di-(m-n-propylphenyl)guanidine; N,N'-di(p-bromo-o-tolyl)guanidine;N-(o-tolyl)-N'-(p-nitro-o-tolyl)guanidine;N-(o-tolyl)-N'-(o-xylyl)guanidine; N,N'-di-(o-xylyl)guanidine;N-(2-adamantyl)-N'-(o-iodophenyl)guanidine;N-(1-adamantanyl)-N'-(o-tolyl)guanidine,N-(3,5-dimethyl-1-adamantanyl)-N'-(o-tolyl)guanidine;N-(3,5-dimethyl-1-adamantyl)-N'-(o-iodophenyl)guanidine;N-(1-adamantyl)-N'-(o-nitrophenyl)guanidine;N-(o-iodophenyl)-N'-(t-butyl)guanidine; N,N'-dibenzylguanidine;N-(adamant-1-yl)-N'-(o-isopropylphenyl)guanidine;N-(adamant-1-yl)-N'-(p-bromo-o-tolyl)guanidine;N-(cyclohexyl)-N'-(p-bromo-o-tolyl)guanidine;N-(adamant-2-yl)-N'-(o-iodophenyl)guanidine;N-(adamant-2-yl)-N'-(o-tolyl)guanidine;N,N'-di(o-methylbenzyl)guanidine; N,N'-di(cyclohexyl)guanidine;N-(cyclohexyl)-N'-(p-iodophenyl)guanidine;N-(cyclohexyl)-N'-(adamantan-1-yl)guanidine; orN,N'-di(1-adamantanemethyl)guanidine.
 31. The method of claim 27 whereinthe guanidine is (+)-N-(2-exonorbornyl)-N'-(2-iodophenyl)guanidine;(-)-N-(2-exonorbornyl)-N'-(2-iodophenyl)guanidine;(+)-N-(2-endonorbornyl)-N'-(2-iodophenyl)guanidine;(-)-N-(2-endonorbornyl)-N'-(2-iodophenyl)guanidine;(+)-N-(2-endonorbornyl)-N'-(o-tolyl)guanidine;(-)-N-(2-endonorbornyl)-N'-(o-tolyl)guanidine;(+)-N-(2-exonorbornyl)-N'-(o-tolyl)guanidine;(-)-N-(2-exonorbornyl)-N'-(o-tolyl)guanidine;(+)-N,N'-di-(endo-2-norbornyl)guanidine;(-)-N,N'-di-(endo-2-norbornyl)guanidine;(+)-N-(exo-2-isobornyl)-N'-(o-iodophenyl)guanidine;(-)-N-(exo-2-isobornyl)-N'-(o-iodophenyl)guanidine;(+)-N,N'-di-(exo-2-norbornyl)-guanidine;(-)-N,N'-di-(exo-2-norbornyl)guanidine;(+)-N-(exo-2-isobornyl)-N'-(o-tolyl)guanidine;N,N'-di-(1-tetralinyl)guanidine; or(-)-N-(exo-2-isobornyl)-N'-(o-tolyl)guanidine.
 32. The method of claim27 wherein the human being has schizophrenia.
 33. The method of claim 27wherein a pharmaceutical composition comprising a pharmaceuticallyacceptable carrier and an anti-psychosis effective amount of theguanidine is administered to the human.
 34. The method of claim 28wherein a pharmaceutical composition comprising a pharmaceuticallyacceptable carrier and an anti-psychosis effective amount of theguanidine is administered orally to the human.
 35. The method of claim28 wherein a pharmaceutical composition comprising a pharmaceuticallyacceptable carrier and an anti-psychosis effective amount of theguanidine is administered parenterally to the human.
 36. The method ofclaim 27 wherein the guanidine is administered as a water-soluble salt.